Hyaluronidase-Expressing Salmonella Effectively Targets Tumor-Associated Hyaluronic Acid in Pancreatic Ductal Adenocarcinoma

Emerging Nanotechnology in Preclinical Pancreatic Cancer Immunotherapy: Driving Towards Clinical Applications

The high malignant degree and poor prognosis of pancreatic cancer (PC) pose severe challenges to the basic research and clinical translation of next-generation therapies. The rise of immunotherapy has improved the treatment of a variety of solid tumors, while the application in PC is highly restricted by the challenge of immunosuppressive tumor microenvironment. The latest progress of nanotechnology as drug delivery platform and immune adjuvant has improved drug delivery in a variety of disease backgrounds and enhanced tumor therapy based on immunotherapy. Based on the immune loop of PC and the status quo of clinical immunotherapy of tumors, this article discussed and critically analyzed the key transformation difficulties of immunotherapy adaptation to the treatment of PC, and then proposed the rational design strategies of new nanocarriers for drug delivery and immune regulation, especially the design of combined immunotherapy. This review also put forward prospective views on future research directions, so as to provide information for the new means of clinical treatment of PC combined with the next generation of nanotechnology and immunotherapy.

Tumor Stroma Content Regulates Penetration and Efficacy of Tumor-targeting Bacteria

Bacteria-based cancer therapy (BBCT) strains grow selectively in primary tumors and metastases, colonize solid tumors independent of genetics, and kill cells resistant to standard molecular therapy. Clinical trials of BBCT in solid tumors have not reported any survival advantage yet, partly due to the limited bacterial colonization. Collagen, abundant in primary and metastatic solid tumors, has a well-known role in hindering intratumoral penetration of therapeutics. Nevertheless, the effect of collagen content on the intratumoral penetration and antitumor efficacy of BBCT is rarely unexplored. We hypothesized that the presence of collagen limits the penetration and, thereby, the antitumor effects of tumor-selective Salmonella. Typhimurium VNP20009 cheY+. We tested our hypothesis in low and high collagen content tumor spheroid models of triple-negative murine breast cancer. We found that high collagen content significantly hinders bacteria transport in tumors, reducing bacteria penetration and distribution by ~7-fold. The higher penetration of bacteria in low collagen-content tumors led to an overwhelming antitumor effect (~73% increase in cell death), whereas only a 28% increase in cell death was seen in the high collagen-content tumors. Our mathematical modeling of intratumoral bacterial colonization delineates the role of growth and diffusivity, suggesting an order of magnitude lower diffusivity in the high collagen-content tumors dominates the observed outcomes. Finally, our single-cell resolution analysis reveals a strong spatial correlation between bacterial spatial localization and collagen content, further corroborating that collagen acts as a barrier to bacterial penetration despite S. Typhimurium VNP20009 cheY+ motility. Understanding the effect of collagen on BBCT performance could lead to engineering more efficacious BBCT strains capable of overcoming this barrier to colonization of primary tumors and metastases.

Intratumoural microbiota: a new frontier in cancer development and therapy

Human microorganisms, including bacteria, fungi, and viruses, play key roles in several physiological and pathological processes. Some studies discovered that tumour tissues once considered sterile actually host a variety of microorganisms, which have been confirmed to be closely related to oncogenesis. The concept of intratumoural microbiota was subsequently proposed. Microbiota could colonise tumour tissues through mucosal destruction, adjacent tissue migration, and hematogenic invasion and affect the biological behaviour of tumours as an important part of the tumour microenvironment. Mechanistic studies have demonstrated that intratumoural microbiota potentially promote the initiation and progression of tumours by inducing genomic instability and mutations, affecting epigenetic modifications, promoting inflammation response, avoiding immune destruction, regulating metabolism, and activating invasion and metastasis. Since more comprehensive and profound insights about intratumoral microbiota are continuously emerging, new methods for the early diagnosis and prognostic assessment of cancer patients have been under examination. In addition, interventions based on intratumoural microbiota show great potential to open a new chapter in antitumour therapy, especially immunotherapy, although there are some inevitable challenges. Here, we aim to provide an extensive review of the concept, development history, potential sources, heterogeneity, and carcinogenic mechanisms of intratumoural microorganisms, explore the potential role of microorganisms in tumour prognosis, and discuss current antitumour treatment regimens that target intratumoural microorganisms and the research prospects and limitations in this field.

Salmonella enterica and outer membrane vesicles are current and future options for cancer treatment

Conventional cancer therapies have many limitations. In the last decade, it has been suggested that bacteria-mediated immunotherapy may circumvent the restrictions of traditional treatments. For example, Salmonella enterica is the most promising bacteria for treating cancer due to its intrinsic abilities, such as killing tumor cells, targeting, penetrating, and proliferating into the tumor. S. enterica has been genetically modified to ensure safety and increase its intrinsic antitumor efficacy. This bacterium has been used as a vector for delivering anticancer agents and as a combination therapy with chemotherapy, radiotherapy, or photothermic. Recent studies have reported the antitumor efficacy of outer membrane vesicles (OMVs) derived from S. enterica. OMVs are considered safer than attenuated bacteria and can stimulate the immune system as they comprise most of the immunogens found on the surface of their parent bacteria. Furthermore, OMVs can also be used as nanocarriers for antitumor agents. This review describes the advances in S. enterica as immunotherapy against cancer and the mechanisms by which Salmonella fights cancer. We also highlight the use of OMVs as immunotherapy and nanocarriers of anticancer agents. OMVs derived from S. enterica are innovative and promising strategies requiring further investigation.

High-level expression and characterization of a highly active hyaluronate lyase HylC with significant potential in hyaluronan oligosaccharide preparation

Hyaluronate lyases (HA lyases) have been proved to distribute widely among microorganisms, with large potential in hyaluronan processing. Here, a highly active HA lyase HylC from Citrobacter freundii strain Cf1 is reported. HylC was expressed in Escherichia coli BL21(DE3) under the regulation of T7 promoter, and purified to electrophoretic homogeneity for enzymatic characterization, which suggested its suitable thermo- and pH stability under 45 °C and pH rang of 4-8, and high halotolerancy in 1.5 M NaCl. The enzyme exhibited the optimal activity under 37 °C and pH 5.5, and was activated by Ca²⁺, K⁺, Zn²⁺, Ni²⁺ and Li⁺. Analysis of degradation product proved it cleave HA in endolytic manner, releasing unsaturated disaccharides as final product. Then, through optimization of promoter and construction of dual promoter, expression level of HylC improved from 1.10 × 10⁴ U/mL to 2.64 × 10⁴ U/mL on shake-flask level. Finally, through batch fermentation, a highest activity of 2.65×10⁵ U/mL was achieved in a 5-L fermenter. Taken together, this work demonstrates the potential of HylC and its recombinant strain in industrial applications. To our knowledge, the HA lyase production reported in this study was the highest level in literatures to date.

ECM-targeting bacteria enhance chemotherapeutic drug efficacy by lowering IFP in tumor mouse models

Bacterial cancer therapies aim to manipulate bacteria to effectively deploy therapeutic payloads to tumors. Attenuated bacteria alone often cannot eradicate solid tumors. Attenuated Salmonella can be engineered to deliver cytotoxic drugs to either trigger an immune response or increase antitumor efficacy when combined with chemotherapeutic drugs. However, the extracellular matrix (ECM) surrounding cancer cells forms a barrier that often limits the ability of chemotherapeutic and cytotoxic drugs to penetrate and eliminate tumors. To overcome this limitation, we developed a strategy to combine chemotherapy with an attenuated Salmonella typhimurium strain engineered to secrete HysA protein (from Staphylococcus aureus; Hyaluronidase, HAase) in tumors. The engineered Salmonella effectively degraded hyaluronan (HA), which is a major ECM constituent in tumors, and suppressed tumor growth in mouse models of pancreatic adenocarcinoma (ASPC-1) and breast cancer (4T1). Furthermore, it prolonged survival when combined with chemotherapeutic drugs (doxorubicin or gemcitabine). Upon bacterial colonization, the HAase-mediated ECM degradation decreased interstitial fluid pressure (IFP) in the tumor microenvironment. Additionally, HA degradation using HAase-expressing bacteria in vivo led to decreased binding to the receptor, CD44, expressed in tumors. This may modulate proliferation- and apoptosis-related signal pathways. Therefore, ECM-targeting bacteria can be used as a synergistic anticancer therapeutic agent to maximize chemotherapeutic drug delivery into highly invasive tumors.

Hyaluronic acid association with bacterial, fungal and viral infections: Can hyaluronic acid be used as an antimicrobial polymer for biomedical and pharmaceutical applications?

The relationships between hyaluronic acid (HA) and pathological microorganisms incite new understandings on microbial infection, tissue penetration, disease progression and lastly, potential treatments. These understandings are important for the advancement of next generation antimicrobial therapeutical strategies for the control of healthcare-associated infections. Herein, this review will focus on the interplay between HA, bacteria, fungi, and viruses. This review will also comprehensively detail and discuss the antimicrobial activity displayed by various HA molecular weights for a variety of biomedical and pharmaceutical applications, including microbiology, pharmaceutics, and tissue engineering.

The Novel SLRP Family Member Lumican Suppresses Pancreatic Cancer Cell Growth

OBJECTIVES

The past studies clearly indicated that lumican was important in the context of pancreatic cancer (PC) onset and progression, but failed to clarify the underlying mechanistic basis for such activity. As such, we evaluated the functional importance of lumican in the context of pancreatic ductal adenocarcinoma (PDAC) to understand its mechanistic role in PC.

METHODS

Lumican levels were evaluated in PDAC patient tissues via quantitative real-time polymerase chain reaction, Western blotting, and immunohistochemistry approaches. The role of lumican was additionally assessed via transfecting PDAC cell lines (BxPC-3, PANC-1) with lumican knockdown or overexpression constructs and treating PDAC cell lines with exogenous recombinant human lumican.

RESULTS

Lumican expression levels were significantly higher in pancreatic tumor tissues relative to healthy paracancerous tissues. Lumican knockdown in BxPC-3 and PANC-1 enhanced their proliferation and migration, but reduced cellular apoptosis. Alternatively, lumican overexpression and exogenous lumican exposure failed to alter the proliferative activity of these cells. Further, lumican knockdown in BxPC-3 and PANC-1 cells results in marked P53 and P21 dysregulation.

CONCLUSIONS

Lumican may suppress PDAC tumor growth by regulating P53 and P21, and the function of lumican sugar chains in the context of PC is worth studying in future studies.

Microbiota in the Natural History of Pancreatic Cancer: From Predisposition to Therapy

Early microbiome insights came from gut microbes and their role among intestinal and extraintestinal disease. The latest evidence suggests that the microbiota is a true organ, capable of several interactions throughout the digestive system, attracting specific interest in the biliopancreatic district. Despite advances in diagnostics over the last few decades and improvements in the management of this disease, pancreatic cancer is still a common cause of cancer death. Microbiota can influence the development of precancerous disease predisposing to pancreatic cancer (PC). At the same time, neoplastic tissue shows specific characteristics in terms of diversity and phenotype, determining the short- and long-term prognosis. Considering the above information, a role for microbiota has also been hypothesized in the different phases of the PC approach, providing future revolutionary therapeutic insights. Microbiota-modulating therapies could open new issues in the therapeutic landscape. The aim of this narrative review is to assess the most updated evidence on microbiome in all the steps regarding pancreatic adenocarcinoma, from early development to response to antineoplastic therapy and long-term prognosis.

Bacteria-mediated cancer therapy: A versatile bio-sapper with translational potential

Bacteria are important symbionts for humans, which sustain substantial influences on our health. Interestingly, some bastrains have been identified to have therapeutic applications, notably for antitumor activity. Thereby, oncologists have developed various therapeutic models and investigated the potential antitumor mechanisms for bacteria-mediated cancer therapy (BCT). Even though BCT has a long history and exhibits remarkable therapeutic efficacy in pre-clinical animal models, its clinical translation still lags and requires further breakthroughs. This review aims to focus on the established strains of therapeutic bacteria and their antitumor mechanisms, including the stimulation of host immune responses, direct cytotoxicity, the interference on cellular signal transduction, extracellular matrix remodeling, neoangiogenesis, and metabolism, as well as vehicles for drug delivery and gene therapy. Moreover, a brief discussion is proposed regarding the important future directions for this fantastic research field of BCT at the end of this review.

Targeted Depletion of Hyaluronic Acid Mitigates Murine Breast Cancer Growth

Hyaluronic acid (HA) is highly elevated in breast cancers compared to normal breast tissue and is associated with increased tumor aggressiveness and poor prognosis. HA interacts with cell-trafficking CD44 receptors to promote tumor cell migration and proliferation and regulates both pro- and anti-inflammatory cytokine production through tumor-associated macrophages. The highly negative charge of HA enables its uptake of vast amounts of water that greatly increases the tumor interstitial fluidic pressure, which, combined with the presence of other extracellular matrix components such as collagen, results in tumor stroma with abnormal vasculature, hypoxia, and increased drug resistance. Thus, the degradation of HA in breast cancer may attenuate growth and improve permeability to anticancer agents. Previous methods to deplete tumor HA have resulted in significant off-tumor effects due to the systemic use of mammalian hyaluronidases. To overcome this, we developed a hyaluronidase-secreting Salmonella typhimurium (YS-HAse) that specifically and preferentially colonizes tumors to deplete HA. We show that the systemic administration of YS-HAse in immunocompetent murine models of breast cancer enhances tumor perfusion, controls tumor growth, and restructures the tumor immune contexture. These studies highlight the utility of YS-HAse as a novel microbial-based therapeutic that may also be combined with existing therapeutic approaches.

Heterogeneous cancer-associated fibroblasts: A new perspective for understanding immunosuppression in pancreatic cancer

Immunotherapy has shown promising efficacy in the treatment of a wide range of cancers; however, it has had little effect on pancreatic cancer. Cancer-associated fibroblasts (CAFs), the predominant mesenchymal cells present in the pancreatic cancer microenvironment, are powerful supporters of the malignant progression of pancreatic cancer. CAFs can modify the microenvironment, establish a refuge to aid cancer cells in immune escape by secreting large amounts of extracellular matrix, and produce soluble cytokines and exosomal vesicles. Hence, CAFs are important contributors to the failure of immunotherapy. Current in-depth studies of CAFs have shown that CAFs are a heterogeneous population of mesenchymal cells; therefore, the functional complexity of their populations needs in-depth explorations in future studies. This review summarizes how heterogeneous CAFs help cancer cells achieve immune escape and suggests potential directions for using CAFs as targets to address immune escape.

Insights into the source, mechanism and biotechnological applications of hyaluronidases

It has long been found that hyaluronidases exist in a variety of organisms, playing their roles in various biological processes including infection, envenomation and metabolic regulation through degrading hyaluronan. However, exploiting them as a bioresource for specific applications had not been extensively studied until the latest decades. In recent years, new application scenarios have been developed, which extended the field of application, and emphasized the research value of hyaluronidase. This critical review comprehensively summarizes existing studies on hyaluronidase from different source, particularly in their structures, action patterns, and biological functions in human and mammals. Furthermore, we give in-depth insight into the resource mining and protein engineering process of hyaluronidase, as well as strategies for their high-level production, indicating that mixed strategies should be adopted to obtain well-performing hyaluronidase with efficiency. In addition, advances in application of hyaluronidase were summarized and discussed. Finally, prospects for future researches are proposed, highlighting the importance of further investigation into the characteristics of hyaluronidases, and the necessity of investigating their products for the development of their application value.

Complex Role of Microbiome in Pancreatic Tumorigenesis: Potential Therapeutic Implications

Pancreatic cancer (PC) is the fourth leading cause of cancer-related mortality with limited diagnostic and therapeutic options. Although immunotherapy has shown promise in the treatment of several cancers, its role in pancreatic cancer is rather limited. Several studies have focused on determining the role of the tumor microenvironment with cancer-cell-intrinsic events and tumor-infiltrating immune cellular properties. However, in the past decade, there has been emerging research aimed at delineating the role of the host microbiome, including the metabolites from microbes and host responses, on pancreatic tumorigenesis. Importantly, there is emerging evidence suggesting the beneficial role of a gut microbiome transplant to improve immunotherapeutic outcomes in cancer patients. In this review, we summarize the recent understanding of the role of the microbiome in pancreatic cancer progression, along with its clinical diagnostic and therapeutic implications.

Bacterially mediated drug delivery and therapeutics: Strategies and advancements

It was already clinically apparent 150 years ago that bacterial therapy could alleviate diseases. Recently, a burgeoning number of researchers have been using bacterial regimens filled with microbial therapeutic leads to diagnose and treat a wide range of disorders and diseases, including cancers, inflammatory diseases, metabolic disorders and viral infections. Some bacteria that were designed to have low toxicity and high efficiency in drug delivery have been used to treat diseases successfully, especially in tumor therapy in animal models or clinical trials, thanks to the progress of genetic engineering and synthetic bioengineering. Therefore, genetically engineered bacteria can serve as efficient drug delivery vehicles, carrying nucleic acids or genetic circuits that encode and regulate therapeutic payloads. In this review, we summarize the development and applications of this approach. Strategies for genetically modifying strains are described in detail, along with their objectives. We also describe some controlled strategies for drug delivery and release using these modified strains as carriers. Furthermore, we discuss treatment methods for various types of diseases using engineered bacteria. Tumors are discussed as the most representative example, and other diseases are also briefly described. Finally, we discuss the challenges and prospects of drug delivery systems based on these bacteria.

The huge clinical potential of microbiota in the treatment of pancreatic cancer: The next frontier

Microbes and their metabolites are found in all body organs; their interaction with body organs can influence inflammation, immunity, and cancer development. Pancreatic cancer development is closely related to intestinal, intrapancreatic, and oral flora. The microbiota plays a regulatory role in pancreatic cancer's malignant progression and treatment resistance. Thus, the study of microbiota-host interactions has emerged as a new hot topic in pancreatic cancer treatment, with microbiota control demonstrating significant clinical potential. This review summarizes recent advances in the clinical diagnosis and treatment of pancreatic cancer, emphasizing the enormous potential for operating microbiota in pancreatic cancer treatment.

Engineered Bacteria Enhance Immunotherapy and Targeted Therapy through Stromal Remodeling of Tumors

Desmoplastic solid tumors are characterized by the rapid build-up of extracellular matrix (ECM) macromolecules, such as hyaluronic acid (HA). The resulting physiological barrier prevents the infiltration of immune cells and also impedes the delivery of anticancer agents. The development of a hypervesiculating Escherichia coli Nissle (ΔECHy) based tumor targeting bacterial system capable of distributing a fusion peptide, cytolysin A (ClyA)-hyaluronidase (Hy) via outer membrane vesicles (OMVs) is reported. The capability of targeting hypoxic tumors, manufacturing recombinant proteins in situ and the added advantage of an on-site OMV based distribution system makes the engineered bacterial vector a unique candidate for peptide delivery. The HA degrading potential of Hy for stromal modulation is combined with the cytolytic activity of ClyA followed by testing it within syngeneic cancer models. ΔECHy is combined with immune checkpoint antibodies and tyrosine kinase inhibitors (TKIs) to demonstrate that remodeling the tumor stroma results in the improvement of immunotherapy outcomes and enhancing the efficacy of biological signaling inhibitors. The biocompatibility of ΔECHy is also investigated to show that the engineered bacteria are effectively cleared, elicit minimal inflammatory and immune responses, and therefore could be a reliable candidate as a live biotherapeutic.

Targeting the extracellular matrix for immunomodulation: applications in drug delivery and cell therapies

Host immune cells interact bi-directionally with their extracellular matrix (ECM) to receive and deposit molecular signals, which orchestrate cellular activation, proliferation, differentiation, and function to maintain healthy tissue homeostasis. In response to pathogens or damage, immune cells infiltrate diseased sites and synthesize critical ECM molecules such as glycoproteins, proteoglycans, and glycosaminoglycans to promote healing. When the immune system misidentifies pathogens or fails to survey damaged cells effectively, maladies such as chronic inflammation, autoimmune diseases, and cancer can develop. In these conditions, it is essential to restore balance to the body through modulation of the immune system and the ECM. This review details the components of dysregulated ECM implicated in pathogenic environments and therapeutic approaches to restore tissue homeostasis. We evaluate emerging strategies to overcome inflamed, immune inhibitory, and otherwise diseased microenvironments, including mechanical stimulation, targeted proteases, adoptive cell therapy, mechanomedicine, and biomaterial-based cell therapeutics. We highlight various strategies that have produced efficacious responses in both pre-clinical and human trials and identify additional opportunities to develop next-generation interventions. Significantly, we identify a need for therapies to address dense or fibrotic tissue for the treatment of organ tissue damage and various cancer subtypes. Finally, we conclude that therapeutic techniques that disrupt, evade, or specifically target the pathogenic microenvironment have a high potential for improving therapeutic outcomes and should be considered a priority for immediate exploration. A schematic showing the various methods of extracellular matrix disruption/targeting in both fibrotic and cancerous environments. a Biomaterial-based cell therapy can be used to deliver anti-inflammatory cytokines, chemotherapeutics, or other factors for localized, slow release of therapeutics. b Mechanotherapeutics can be used to inhibit the deposition of molecules such as collagen that affect stiffness. c Ablation of the ECM and target tissue can be accomplished via mechanical degradation such as focused ultrasound. d Proteases can be used to improve the distribution of therapies such as oncolytic virus. e Localization of therapeutics such as checkpoint inhibitors can be improved with the targeting of specific ECM components, reducing off-target effects and toxicity.

Collagenase-Expressing Salmonella Targets Major Collagens in Pancreatic Cancer Leading to Reductions in Immunosuppressive Subsets and Tumor Growth

Therapeutic resistance in pancreatic ductal adenocarcinoma (PDAC) can be attributed, in part, to a dense extracellular matrix containing excessive collagen deposition. Here, we describe a novel Salmonella typhimurium (ST) vector expressing the bacterial collagenase Streptomyces omiyaensis trypsin (SOT), a serine protease known to hydrolyze collagens I and IV, which are predominantly found in PDAC. Utilizing aggressive models of PDAC, we show that ST-SOT selectively degrades intratumoral collagen leading to decreases in immunosuppressive subsets, tumor proliferation and viability. Ultimately, we found that ST-SOT treatment significantly modifies the intratumoral immune landscape to generate a microenvironment that may be more conducive to immunotherapy.

On-Demand Antimicrobial Agent Release from Functionalized Conjugated Oligomer-Hyaluronic Acid Nanoparticles for Tackling Antimicrobial Resistance

Controllable drug release is promising for fighting against antimicrobial resistance, which is a critical threat to human health worldwide. Herein, new hyaluronidase-responsive conjugated oligo(thiophene ethynylene) (OTE)-covalently modified hyaluronic acid (OTE-HA) nanoparticles for on-demand release of antimicrobial agents are reported. The synthesis of amphiphilic OTE-HA was carried out by esterification reaction. The resulting macromolecules were self-assembled in water to form nanoparticles, in which the hydrophobic OTE section, as bactericides, formed "cores" and the hydrophilic hyaluronic acid (HA) formed "shells". The OTE-HA nanoparticles avoid bactericide premature leakage and effectively block the dark cytotoxicity of the OTE section, possessing excellent biocompatibility. Using methicillin-resistant Staphylococcus aureus (MRSA) as an example, hyaluronidase, largely secreted by MRSA, can in situ trigger the release of OTE via hydrolyzing OTE-HA nanoparticles into fragments, even disaccharides linked with OTE. Importantly, the OTE section could effectively break cell membranes, leading to bacterial death. The half-maximal inhibitory concentration of the nanoparticles against MRSA is 3.3 μg/mL. The great antibacterial activity of OTE-HA nanoparticles against Gram-positive bacteria Streptococcus pneumoniae further confirms the controllable bactericide delivery mechanism. OTE-HA nanoparticles coated on a surface can also effectively inhibit the growth of bacteria, which holds a remarkable promise in biomedical applications. Therefore, this work provides a favorable strategy of on-demand and in situ drug release for sterilization and defeating antimicrobial resistance.

Salmonella-Based Therapy Targeting Indoleamine 2,3-Dioxygenase Restructures the Immune Contexture to Improve Checkpoint Blockade Efficacy

Therapeutic options for non-small cell lung cancer (NSCLC) treatment have changed dramatically in recent years with the advent of novel immunotherapeutic approaches. Among these, immune checkpoint blockade (ICB) using monoclonal antibodies has shown tremendous promise in approximately 20% of patients. In order to better predict patients that will respond to ICB treatment, biomarkers such as tumor-associated CD8⁺ T cell frequency, tumor checkpoint protein status and mutational burden have been utilized, however, with mixed success. In this study, we hypothesized that significantly altering the suppressive tumor immune landscape in NSCLC could potentially improve ICB efficacy. Using sub-therapeutic doses of our Salmonella typhimurium-based therapy targeting the suppressive molecule indoleamine 2,3-dioxygenase (shIDO-ST) in tumor-bearing mice, we observed dramatic changes in immune subset phenotypes that included increases in antigen presentation markers, decreased regulatory T cell frequency and overall reduced checkpoint protein expression. Combination shIDO-ST treatment with anti-PD-1/CTLA-4 antibodies enhanced tumor growth control, compared to either treatment alone, which was associated with significant intratumoral infiltration by CD8⁺ and CD4⁺ T cells. Ultimately, we show that increases in antigen presentation markers and infiltration by T cells is correlated with significantly increased survival in NSCLC patients. These results suggest that the success of ICB therapy may be more accurately predicted by taking into account multiple factors such as potential for antigen presentation and immune subset repertoire in addition to markers already being considered. Alternatively, combination treatment with agents such as shIDO-ST could be used to create a more conducive tumor microenvironment for improving responses to ICB.

Targeting desmoplasia in pancreatic cancer as an essential first step to effective therapy

Pancreatic cancer is considered one of the most lethal cancers in the US. It contributes to an estimated 47,000 deaths annually and is predicted to surpass prostate, breast and colorectal cancers as the leading cause of cancer-related death. Although major advancements in cancer treatment have improved outcomes for many cancer types, survival rate for pancreatic cancer has not improved in nearly four decades despite tremendous effort. One attribute of pancreatic cancer that is considered a major barrier to effective treatment is the formation of fibrotic tissue around tumor cells known as desmoplasia. A number of promising approaches have been developed to deplete fibrotic components in pancreatic tumors to enhance drug delivery, some of which have been tested in clinical trials of advanced, unresectable pancreatic cancer. Here, we discuss previous efforts, shortcomings and new considerations for developing more effective agents to eliminate desmoplasia.

Surface engineering of nanoparticles with ligands for targeted delivery to osteosarcoma

Osteosarcoma is one of the most common malignant bone tumors which affect adolescents. Neoadjuvant chemotherapy followed by operation has become recommended for osteosarcoma treatment. Whereas, the effects of conventional chemotherapy are unsatisfactory because of multidrug resistance, fast clearance rate, nontargeted delivery, side effects and so on. Accordingly, Nanoparticle-mediated targeted drug delivery system (NTDDS) is recommended to be a novel treatment strategy for osteosarcoma. NTDDS can overcome the above obstacles by enhanced permeability and retention effect and active targeting. The active targeting of the delivery system is mainly based on ligands. In this study, we investigate and summarize the most common ligands used in the latest NTDDS for osteosarcoma. It might provide new insights into nanomedicine for osteosarcoma treatment.