Improved Cancer Immunochemotherapy via Optimal Co-delivery of Chemotherapeutic and Immunomodulatory Agents

Simultaneous assaying of NLG919, tryptophan and kynurenine by ultrahigh performance LC-MS in pharmacokinetics and biodistribution studies

Background: Indocyanine2,3-dioxygenase (IDO) is an enzyme that can catalyze the metabolism of tryptophan (Trp) into kynurenine (Kyn), thus inhibiting the tumor immune microenvironment. Method: Based on its inhibitor, NLG919(NLG), the authors developed a new immunomodulatory polymer micelle and established and verified an ultrahigh performance liquid chromatography-mass spectrometry method for the simultaneous determination of NLG, Trp and Kyn in mouse tumors through the ratio determination of Trp/Kyn tissue distribution and pharmacokinetics. The linear range of the method was 0.001-10 μg/ml. Results: Compared with NLG solution, the immunomodulatory polymeric drug-loaded micelles based on polystyrene-arginine showed higher Trp/Kyn ratio, more tumor aggregation and good pharmacokinetics. Conclusion: This method has been successfully applied to the simultaneous determination of Trp/Kyn and NLG in tumor tissues of mice.

Engineering a folic acid-decorated ultrasmall gemcitabine nanocarrier for breast cancer therapy: Dual targeting of tumor cells and tumor-associated macrophages

Combination of passive targeting with active targeting is a promising approach to improve the therapeutic efficacy of nanotherapy. However, most reported polymeric systems have sizes above 100 nm, which limits effective extravasation into tumors that are poorly vascularized and have dense stroma. This will, in turn, limit the overall effectiveness of the subsequent uptake by tumor cells via active targeting. In this study, we combined the passive targeting via ultra-small-sized gemcitabine (GEM)-based nanoparticles (NPs) with the active targeting provided by folic acid (FA) conjugation for enhanced dual targeted delivery to tumor cells and tumor-associated macrophages (TAMs). We developed an FA-modified prodrug carrier based on GEM (PGEM) to load doxorubicin (DOX), for co-delivery of GEM and DOX to tumors. The co-delivery system showed small particle size of ∼10 nm in diameter. The ligand-free and FA-targeted micelles showed comparable drug loading efficiency and a sustained DOX release profile. The FA-conjugated micelles effectively increased DOX uptake in cultured KB cancer cells that express a high level of folate receptor (FR), but no obvious increase was observed in 4T1.2 breast cancer cells that have a low-level expression of FR. Interestingly, in vivo, systemic delivery of FA-PGEM/DOX led to enhanced accumulation of the NPs in tumor and drastic reduction of tumor growth in a murine 4T1.2 breast cancer model. Mechanistic study showed that 4T1.2 tumor grown in mice expressed a significantly higher level of FOLR2, which was selectively expressed on TAMs. Thus, targeting of TAM may also contribute to the improved in vivo targeted delivery and therapeutic efficacy.

Light-Triggered Efficient Sequential Drug Delivery of Biomimetic Nanosystem for Multimodal Chemo-, Antiangiogenic, and Anti-MDSC Therapy in Melanoma

In view of the multiple pathological hallmarks of tumors, nanosystems for the sequential delivery of various drugs whose targets are separately located inside and outside tumor cells are desired for improved cancer therapy. However, current sequential delivery is mainly achieved through enzyme- or acid-dependent degradation of the nanocarrier, which would be influenced by the heterogeneous tumor microenvironment, and unloading efficiency of the drug acting on the target outside tumor cells is usually unsatisfactory. Here, a light-triggered sequential delivery strategy based on a liposomal formulation of doxorubicin (DOX)-loaded small-sized polymeric nanoparticles (DOX-NP) and free sunitinib in the aqueous cavity, is developed. The liposomal membrane is doped with photosensitizer porphyrin-phospholipid (PoP) and hybridized with red blood cell membrane to confer biomimetic features. Near-infrared light-induced membrane permeabilization triggers the "ultrafast" and "thorough" release of sunitinib (100% release in 5 min) for antiangiogenic therapy and also myeloid-derived suppressor cell (MDSC) inhibition to reverse the immunosuppressive tumor environment. Subsequently, the small-sized DOX-NP liberated from the liposomes is more easily uptaken by tumor cells for improved immunogenic chemotherapy. RNA sequencing and immune-related assay indicates therapeutic immune enhancement. This light-triggered sequential delivery strategy demonstrates the potency in cancer multimodal therapy against multiple targets in different spatial positions in tumor microenvironment.

Self-Assembled Micelles of Amphiphilic PEGylated Drugs for Cancer Treatment

Generally, poor solubility and imprecise delivery of chemotherapeutic drugs can compromise their efficacies for clinical cancer treatment. In order to address such concerns, poor water-soluble drugs are conjugated with poly(ethylene glycol) (PEG) to obtain PEGylated drugs, which have improved water solubility and can also self-assemble in an aqueous solution to form micelles (PEGylated drug micelles). The surface PEG layer enhances the micelles' colloidal stability and reduces the interaction with physiological surroundings. Meanwhile, PEGylated drug micelles are tumor- targeting via the enhanced permeation and retention (EPR) effect to improve antitumor efficacy in comparison with free drugs. PEGylated drug micelles employ drugs as parts of the carrier medium, which increases the micelles' drug loading capacity relatively. The development of stimuli- responsive PEGylated drug micelles facilitates the drug release to be smart and controllable. Moreover, the PEGylated drug micelles show great potentials in overcoming the challenges of cancer therapy, such as multidrug resistance (MDR), angiogenesis, immunosuppression, and so on. In this review, we highlight the research progresses of PEGylated drug micelles, including the structures and properties, smart stimuli-responsive PEGylated drug micelles, and the challenges that have been overcome by PEGylated drug micelles.

Nanomaterials Enhance the Immunomodulatory Effect of Molecular Targeted Therapy

Molecular targeted therapy, a tumor therapy strategy that inhibits specific oncogenic targets, has been shown to modulate the immune response. In addition to directly inhibiting the proliferation and metastasis of tumor cells, molecular targeted drugs can activate the immune system through a variety of mechanisms, including by promoting tumor antigen processing and presentation, increasing intratumoral T cell infiltration, enhancing T cell activation and function, and attenuating the immunosuppressive effect of the tumor microenvironment. However, poor water solubility, insufficient accumulation at the tumor site, and nonspecific targeting of immune cells limit their application. To this end, a variety of nanomaterials have been developed to overcome these obstacles and amplify the immunomodulatory effects of molecular targeted drugs. In this review, we summarize the impact of molecular targeted drugs on the antitumor immune response according to their mechanisms, highlight the advantages of nanomaterials in enhancing the immunomodulatory effect of molecular targeted therapy, and discuss the current challenges and future prospects.

Engineered Multifunctional Nano- and Biological Materials for Cancer Immunotherapy

Cancer immunotherapy is set to emerge as the future of cancer therapy. However, recent immunotherapy trials in different cancers have yielded sub-optimal results, with durable responses seen in only a small fraction of patients. Engineered multifunctional nanomaterials and biological materials are versatile platforms that can elicit strong immune responses and improve anti-cancer efficacy when applied to cancer immunotherapy. While there are traditional systems such as polymer- and lipid-based nanoparticles, there is a wide variety of other materials with inherent and additive properties that can allow for more potent activation of the immune system. By synthesizing and applying multifunctional strategies, it allows for a more extensive and more effective repertoire of tools to use in the wide variety of situations that cancer presents itself. Here, several types of nanoscale and biological material strategies and platforms that provide their inherent benefits for targeting and activating multiple aspects of the immune system are discussed. Overall, this review aims to provide a comprehensive understanding of recent advances in the field of multifunctional cancer immunotherapy and trends that pave the way for more diverse and tactical regression of tumors through soliciting responses by either the adaptive or innate immune system, and even both simultaneously.

Overcome the tumor immunotherapy resistance by combination of the HDAC6 inhibitors with antitumor immunomodulatory agents

Tumor immunotherapy is currently subject of intense scientific and clinical developments. In previous decade, therapists used natural immune system from the human body to treat several diseases. Although tumor immune disease is a big challenge, combinatorial therapeutic strategy has been succeeded to show the clinical significance. In this context, we discuss the HDAC6 and tumor immune diseases relationship. Also, we summarized the current state of knowledge that based on the combination treatments of the HDAC6 inhibitors (HDAC6is) with antitumor immunomodulatory agents. We observed that, the combination therapies slow down the tumor immune diseases by blocking the aggresome and proteasome pathway. The combination therapy was able to reduce M2 macrophage and increasing PD-L1 blockade sensitivity. Most importantly, multiple combinations of HDAC6is with other agents may consider as potential strategies to treat tumor immune diseases, by reducing the side effects and improve efficacy for the future clinical development.

Delivery of gefitinib with an immunostimulatory nanocarrier improves therapeutic efficacy in lung cancer

Background

Combining different cancer treatments represents a promising strategy to improve the therapeutic outcome for lung cancer patients with or without druggable gene alterations.

Methods

We previously developed a polyethylene glycol-based (PEG-based) immunostimulatory nanocarrier (PEG_2k-Fmoc-NLG919) which can efficiently co-deliver an indoleamine 2,3-dioxygenase-1 (IDO1) inhibitor and the chemotherapeutic agent, paclitaxel. This method was found to improve cancer therapy by simultaneously performing immuno- and chemo-therapy. However, whether this nanocarrier could deliver targeted drugs to implement targeted therapy together with immunotherapy remains unclear.

Results

Here, we report that the delivery of the classical tyrosine kinase inhibitor (TKI), gefitinib, with the optimized PEG_5k-Fmoc-NLG919 nanocarrier, increased the sensitivity of lung cancer cells to gefitinib in vitro. Gefitinib was gradually but sufficiently released from the nanocarrier with comparable capacity to inhibit epidermal growth factor receptor (EGFR) activity as using free gefitinib directly. More importantly, treatment with gefitinib-loaded PEG_5k-Fmoc-NLG919 could suppress lung tumor development more efficiently than gefitinib alone in vivo by inducing an immune active microenvironment with more functional CD8⁺ T cells and less regulatory T cell infiltration.

Conclusions

Our study therefore demonstrates that delivery of small molecular targeted drugs with the immunostimulatory nanocarrier is a straightforward strategy for improving antitumor response for lung cancer therapy.

Nanomedicine of tyrosine kinase inhibitors

Recent progress in nanomedicine and targeted therapy brings new breeze into the field of therapeutic applications of tyrosine kinase inhibitors (TKIs). These drugs are known for many side effects due to non-targeted mechanism of action that negatively impact quality of patients' lives or that are responsible for failure of the drugs in clinical trials. Some nanocarrier properties provide improvement of drug efficacy, reduce the incidence of adverse events, enhance drug bioavailability, helps to overcome the blood-brain barrier, increase drug stability or allow for specific delivery of TKIs to the diseased cells. Moreover, nanotechnology can bring new perspectives into combination therapy, which can be highly efficient in connection with TKIs. Lastly, nanotechnology in combination with TKIs can be utilized in the field of theranostics, i.e. for simultaneous therapeutic and diagnostic purposes. The review provides a comprehensive overview of advantages and future prospects of conjunction of nanotransporters with TKIs as a highly promising approach to anticancer therapy.

Paclitaxel/sunitinib-loaded micelles promote an antitumor response in vitro through synergistic immunogenic cell death for triple-negative breast cancer

Chemotherapy-induced immunogenic cell death (ICD) may offer a strategy to improve the effect of the therapeutic treatment of triple-negative breast cancer (TNBC) by eliciting broad antitumor immunity. However, chemotherapy shows a limited therapeutic effect because of multi-drug resistance and the immunosuppressive tumor microenvironment (TME) of TNBC. The unique pharmacological actions of sunitinib (SUN) indicate its possible synergies with paclitaxel (PTX) to enhance chemo-immunotherapy for TNBC. Here, we prepared a co-delivery platform composed of poly(styrene-co-maleic anhydride) (SMA) via a self-assembly process for a combination of PTX and SUN, which was able to induce a higher synergistic ICD. The nanomicellar delivery of PTX and SUN loaded at an optimal ratio of 1:5 (PTX:SUN) presented the characteristics of an appropriate particle size, long-term stability, and time sequence release which synergistically promoted the apoptosis of MDA-MB-231 tumor cells. Moreover, we demonstrated that the combination of PTX and SUN could significantly induce a synergistic effect because it promoted an ICD response, improved tumor immunogenicity, and regulated immunosuppressive factors in the TME. Overall, PTX and SUN with synergistic effects entrapped in a self-assembly nano-delivery system could offer the potential for clinical applicationof a combination chemo-immunotherapy strategy to improve the effect of the therapeutic treatment of TNBC.

Codelivered Chemotherapeutic Doxorubicin via a Dual-Functional Immunostimulatory Polymeric Prodrug for Breast Cancer Immunochemotherapy

Immunochemotherapy is viewed as a promising approach for cancer therapy via combination treatment with immune-modulating drugs and chemotherapeutic drugs. A novel dual-functional immunostimulatory polymeric prodrug carrier PEG_2k-Fmoc-1-MT was developed for simultaneously delivering 1-methyl tryptophan (1-MT) of an indoleamine 2,3-dioxygenase (IDO) inhibitor and chemotherapeutic doxorubicin (DOX) for breast cancer immunochemotherapy. DOX/PEG_2k-Fmoc-1-MT micelles were more effective in cell proliferation inhibition and apoptosis induction in 4T1 cells. PEG_2k-Fmoc-1-MT prodrug micelles presented enhanced inhibition ability of IDO with decreased kynurenine production and increased the proliferation in dose-dependent manners of effector CD4⁺ and CD8⁺ T cells. DOX/PEG_2k-Fmoc-1-MT micelles exhibited prolonged blood circulation time and superior accumulation of DOX and 1-MT in tumors compared to that of DOX and 1-MT solutions. A significantly enhanced immune response of the DOX/PEG_2k-Fmoc-1-MT micelles was observed with the decreasing tryptophan/kynurenine ratio in blood and tumor tissue, promoting effector CD4⁺ and CD8⁺ T cells while reducing regulatory T cell (Tregs) expression. Meanwhile, the coreleased DOX-triggered immunogenic cell death action combined with the cleaved 1-MT promoted the related cytokine secretion of tumor necrosis factor-α, interleukin-2, and interferon-γ, further facilitating the T cell-mediated immune responses. More importantly, the DOX-loaded micelles led to a significantly improved inhibition on tumor growth and prolonged animal survival rate in a 4T1 murine breast cancer model. In conclusion, DOX codelivered by a PEG_2k-Fmoc-1-MT immunostimulatory polymeric prodrug showed a maximum immunochemotherapy efficacy against breast cancer.

Remodeling the fibrotic tumor microenvironment of desmoplastic melanoma to facilitate vaccine immunotherapy

Highly fibrotic and collagen-rich properties in desmoplastic melanoma (DM) result in an immune-suppressive fibrotic tumor microenvironment (TME) that resists clinical therapies. The different clinical and pathological properties, as compared to conventional melanoma, lead to delayed diagnosis and it is difficult to deliver drugs effectively due to fibrosis. Herein, we designed a chemo-immuno strategy focused on combining vaccination immunotherapy with multi-targeting sunitinib (SUN) nano-therapy to remodel TME and generate a robust immune response and a stronger synergistic anti-cancer effect. This strategy was evaluated side-by-side with non-desmoplastic melanoma and achieved significant improvement in therapeutic efficacy. The combination treatment was also synergistically assessed with the desmoplastic melanoma model. This strategy can remodel the fibrotic immunosuppressive TME and result in a robust cytotoxic T-cell response by reducing the collagen content, normalizing blood vessels, inhibiting tumor-associated fibroblasts and reducing high levels of suppressor immune cells. The modification of fibrotic immunosuppressive TME may serve as a good approach to further enhance immunotherapy for desmoplastic tumors.

Nano-encapsulated tryptanthrin derivative for combined anticancer therapy via inhibiting indoleamine 2,3-dioxygenase and inducing immunogenic cell death

Aim: We developed a polycaprolactone-based nanoparticle (NP) to encapsulate tryptanthrin derivative CY-1-4 and evaluated its antitumor efficacy. Materials & methods: CY-1-4 NPs were prepared and evaluated for their cytotoxicity and associated mechanisms, indoleamine 2,3-dioxygenase (IDO)-inhibitory ability, immunogenic cell death (ICD)-inducing ability and antitumor efficacy. Results: CY-1-4 NPs were 123 nm in size. In vitro experiments indicated that they could both induce ICD and inhibit IDO. In vivo studies indicated that a medium dose reduced 58% of the tumor burden in a B16-F10-bearing mouse model, decreased IDO expression in tumor tissues and regulated lymphocytes subsets in spleen and tumors. Conclusion: CY-1-4 is a potential antitumor candidate that could act as a single agent with combined functions of IDO inhibition and ICD induction.

PEG-Derivatized Dual-Functional Nanomicelles for Improved Cancer Therapy

Polymeric micelles have attracted considerable attention for effective delivery of poorly water-soluble cancer drugs. Polyethylene glycol (PEG), which has been approved for human use by the US Food and Drug Administration, is the most commonly used hydrophilic component of polymeric micelles because it is biocompatible and biodegradable. One disadvantage of traditional polymeric micelles is that they include a large amount of inert carrier materials, which do not contribute to therapeutic activity but increase cost and toxicity risk. A better alternative may be "dual-functional" micellar carriers, in which the hydrophobic carrier material (conjugated to PEG) has intrinsic therapeutic activity that complements, or even synergizes with, the antitumor activity of the drug cargo. This review summarizes recent progress in the development of PEG-derivatized dual-functional nanomicelles and surveys the evidence of their feasibility and promise for cancer therapy.

Combination of Sunitinib and PD-L1 Blockade Enhances Anticancer Efficacy of TLR7/8 Agonist-Based Nanovaccine

Cancer vaccines composed of tumor-associated antigens (TAAs) and toll-like receptor (TLR) agonists have shown promising antitumor efficacy in preclinical studies by generating antigen-specific CD8 T cells, but translation of cancer vaccines to the clinic has been limited due to variables responses and development of resistance. The tumor microenvironment deploys various immune escape mechanisms that neutralize CD8 T cell-mediated tumor rejection. Therefore, we hypothesized that modulation of the tumor microenvironment can augment CD8 T cell activation and enhance therapeutic efficacy of cancer vaccines. To accomplish this, we aimed to eliminate immune suppressive cells and block their inhibitory signaling. Combination of the tyrosine kinase inhibitor (TKI) sunitinib with a nanoparticle-based cancer vaccine (nanovaccine) resulted in the reduction of immune-suppressive myeloid-derived suppressive cells (MDSCs) and regulatory T cells (Tregs). Blockade of programmed death-ligand 1 (PD-L1) using anti-PD-L1 antibody was used to reduce CD8 T cell exhaustion. Combination of nanovaccine+sunitinib+PD-L1 antibody treatment reduced PD-L1^high M2 macrophages and MDSCs and upregulated activation of CD8 T cells in the tumor. Nanovaccine+sunitinib+PD-L1 antibody treatment also stimulated antigen-specific CD8 T cell response, which led to improved therapeutic efficacy in MB49 and B16F10 murine tumor models. These results suggest that modulation of tumor microenvironment using sunitinib and PD-L1 blockade can significantly enhance the antitumor efficacy of cancer nanovaccine.