The antitumor immune responses induced by nanoemulsion-encapsulated MAGE1-HSP70/SEA complex protein vaccine following peroral administration route

Diversity of extracellular HSP70 in cancer: advancing from a molecular biomarker to a novel therapeutic target

Heat shock protein 70 (HSP70) is a highly conserved protein functioning as a "molecular chaperone", which is integral to protein folding and maturation. In addition to its high expression within cells upon stressful challenges, HSP70 can be translocated to the cell membrane or released from cells in free form or within extracellular vesicles (EVs). Such trafficking of HSP70 is also present in cancer cells, as HSP70 is overexpressed in various types of patient samples across a range of common malignancies, signifying that extracellular HSP70 (eHSP70) can serve as a tumor biomarker. eHSP70 is involved in a broad range of cancer-related events, including cell proliferation and apoptosis, extracellular matrix (ECM) remodeling, epithelial-mesenchymal transition (EMT), angiogenesis, and immune response. eHSP70 can also induce cancer cell resistance to various treatments, such as chemotherapy, radiotherapy, and anti-programmed death-1 (PD-1) immunotherapy. Though the role of eHSP70 in tumors is contradictory, characterized by both pro-tumor and anti-tumor effects, eHSP70 serves as a promising target in cancer treatment. In this review, we comprehensively summarized the current knowledge about the role of eHSP70 in cancer progression and treatment resistance and discussed the feasibility of eHSP70 as a cancer biomarker and therapeutic target.

Protein-Based Nanocarriers and Nanotherapeutics for Infection and Inflammation

Infectious and inflammatory diseases are one of the leading causes of death globally. The status quo has become more prominent with the onset of the coronavirus disease 2019 (COVID-19) pandemic. To combat these potential crises, proteins have been proven as highly efficacious drugs, drug targets, and biomarkers. On the other hand, advancements in nanotechnology have aided efficient and sustained drug delivery due to their nano-dimension-acquired advantages. Combining both strategies together, the protein nanoplatforms are equipped with the advantageous intrinsic properties of proteins as well as nanoformulations, eloquently changing the field of nanomedicine. Proteins can act as carriers, therapeutics, diagnostics, and theranostics in their nanoform as fusion proteins or as composites with other organic/inorganic materials. Protein-based nanoplatforms have been extensively explored to target the major infectious and inflammatory diseases of clinical concern. The current review comprehensively deliberated proteins as nanocarriers for drugs and nanotherapeutics for inflammatory and infectious agents, with special emphasis on cancer and viral diseases. A plethora of proteins from diverse organisms have aided in the synthesis of protein-based nanoformulations. The current study specifically presented the proteins of human and pathogenic origin to dwell upon the field of protein nanotechnology, emphasizing their pharmacological advantages. Further, the successful clinical translation and current bottlenecks of the protein-based nanoformulations associated with the infection-inflammation paradigm have also been discussed comprehensively. SIGNIFICANCE STATEMENT: This review discusses the plethora of promising protein-based nanocarriers and nanotherapeutics explored for infectious and inflammatory ailments, with particular emphasis on protein nanoparticles of human and pathogenic origin with reference to the advantages, ADME (absorption, distribution, metabolism, and excretion parameters), and current bottlenecks in development of protein-based nanotherapeutic interventions.

HSP70 Family in Cancer: Signaling Mechanisms and Therapeutic Advances

The 70 kDa heat shock proteins (HSP70s) are a group of highly conserved and inducible heat shock proteins. One of the main functions of HSP70s is to act as molecular chaperones that are involved in a large variety of cellular protein folding and remodeling processes. HSP70s are found to be over-expressed and may serve as prognostic markers in many types of cancers. HSP70s are also involved in most of the molecular processes of cancer hallmarks as well as the growth and survival of cancer cells. In fact, many effects of HSP70s on cancer cells are not only related to their chaperone activities but rather to their roles in regulating cancer cell signaling. Therefore, a number of drugs directly or indirectly targeting HSP70s, and their co-chaperones have been developed aiming to treat cancer. In this review, we summarized HSP70-related cancer signaling pathways and corresponding key proteins regulated by the family of HSP70s. In addition, we also summarized various treatment approaches and progress of anti-tumor therapy based on targeting HSP70 family proteins.

Emerging vaccine nanotechnology: From defense against infection to sniping cancer

Looking retrospectively at the development of humanity, vaccination is an unprecedented medical landmark that saves lives by harnessing the human immune system. During the ongoing coronavirus disease 2019 (COVID-19) pandemic, vaccination is still the most effective defense modality. The successful clinical application of the lipid nanoparticle-based Pfizer/BioNTech and Moderna mRNA COVID-19 vaccines highlights promising future of nanotechnology in vaccine development. Compared with conventional vaccines, nanovaccines are supposed to have advantages in lymph node accumulation, antigen assembly, and antigen presentation; they also have, unique pathogen biomimicry properties because of well-organized combination of multiple immune factors. Beyond infectious diseases, vaccine nanotechnology also exhibits considerable potential for cancer treatment. The ultimate goal of cancer vaccines is to fully mobilize the potency of the immune system as a living therapeutic to recognize tumor antigens and eliminate tumor cells, and nanotechnologies have the requisite properties to realize this goal. In this review, we summarize the recent advances in vaccine nanotechnology from infectious disease prevention to cancer immunotherapy and highlight the different types of materials, mechanisms, administration methods, as well as future perspectives.

Boosting Natural Killer Cell-Based Cancer Immunotherapy with Selenocystine/Transforming Growth Factor-Beta Inhibitor-Encapsulated Nanoemulsion

Natural killer (NK) cell-based immunotherapy represents a promising strategy to overcome the bottlenecks of cancer treatment. However, the therapeutic efficacy is greatly limited by downregulation of recognition ligands on the tumor cell surface, and the immunosuppressive effects can be thwarted by the tumor microenvironment such as secretion of transforming growth factor-beta (TGF-β), which could stunt the NK cell-mediated immune response. To overcome these limitations, herein we developed a nanoemulsion system (SSB NMs) to co-deliver TGF-β inhibitor and selenocysteine (SeC) to achieve amplified anticancer efficacy. SSB NMs significantly enhanced the lytic potency of NK92 cells by 2.1-fold. Moreover, a subtoxic dose of SSB NMs effectively sensitized MDA-MB-231 triple-negative breast cancer (TNBC) cells to NK cells derived from seven clinical patients, resulting in an up to 13.8-fold increase in cancer lysis. Mechanistic studies reveal that the sensitizing effects relied on natural killer group 2, member D (NKG2D)/NKG2D ligands (NKG2DLs) signaling with the involvement of DNA damage response. SSB NMs also effectively restrained TGF-β/TGF-β RI/Smad2/3 signaling, which thus enhanced NKG2DL expression on tumor cells and stimulated NKG2D surface expression on NK92 cells, ultimately contributing to the enhanced immune response. Furthermore, SSB NMs sustained release of SeC and TGF-β inhibitor and synergized with NK92 cells to induce significant anticancer effects in vivo. Together, this study not only demonstrates a simple strategy for the design of a nanoemulsion to co-deliver synergistic drugs but also sheds light on the application and action mechanisms in NK cell adaptive therapy against breast cancer, especially TNBCs.

Preparation of a new combination nanoemulsion-encapsulated MAGE1-MAGE3-MAGEn/HSP70 vaccine and study of its immunotherapeutic effect

BACKGROUND

MAGE family genes have been studied as targets for tumor immunotherapy for a long time. Here, we combined MAGE1-, MAGE3- and MAGEn-derived peptides as a cancer vaccine and tested whether a new combination nanoemulsion-encapsulated vaccine could be used to inhibit the growth of tumor cells in humanized SCID mice.

METHODS

The nanoemulsion-encapsulated complex protein vaccine (MAGE1, MAGE3, and MAGEn/HSP70 fusion protein; M1M3MnH) was prepared using a magnetic ultrasonic technique. After screening, human PBMCs were injected into SCID mice to mimic the human immune system. Then, the humanized SCID mice were challenged with M3-HHCC cells and immunized with nanoemulsion-encapsulated MAGE1-MAGE3-MAGEn/HSP70 [NE(M1M3MnH)] or M1M3MnH. The cellular immune responses were detected by IFN-γ ELISPOT and cytotoxicity assays. Therapeutic and tumor challenge experiments were also performed.

RESULTS

The results showed that the immune responses elicited by NE(M1M3MnH) were apparently stronger than those elicited by M1M3MnH, NE(-) or PBS, suggesting that this novel nanoemulsion carrier induces potent antitumor immunity against the encapsulated antigens. The results of the therapeutic and tumor challenge experiments also indicated that the new vaccine had a definite effect on SCID mice bearing human hepatic cancer.

CONCLUSION

Our study indicated that the combination of several tumor antigen-derived peptides may be a relatively good strategy for peptide-based cancer immunotherapy. These results suggest that the complex nanoemulsion vaccine could have broader applications for both therapy and prevention mediated by antitumor effects in the future.

Current and New Approaches for Mucosal Vaccine Delivery

Mucosal surfaces are the interface between the host’s internal milieu and the external environment, and they have dual functions, serving as physical barriers to foreign antigens and as accepting sites for vital materials. Mucosal vaccines are more favored to prevent mucosal infections from the portal of entry. Although mucosal vaccination has many advantages, licensed mucosal vaccines are scarce. The most widely studied mucosal routes are oral and intranasal. Licensed oral and intranasal vaccines are composed mostly of whole cell killed or live attenuated microorganisms serving as both delivery systems and built-in adjuvants. Future mucosal vaccines should be made with more purified antigen components, which will be relatively less immunogenic. To induce robust protective immune responses against well-purified vaccine antigens, an effective mucosal delivery system is an essential requisite. Recent developments in biomaterials and nanotechnology have enabled many innovative mucosal vaccine trials. For oral vaccination, the vaccine delivery system should be able to stably carry antigens and adjuvants and resist harsh physicochemical conditions in the stomach and intestinal tract. Besides many nano/microcarrier tools generated by using natural and chemical materials, the development of oral vaccine delivery systems using food materials should be more robustly researched to expand vaccine coverage of gastrointestinal infections in developing countries. For intranasal vaccination, the vaccine delivery system should survive the very active mucociliary clearance mechanisms and prove safety because of the anatomical location of nasal cavity separated by a thin barrier. Future mucosal vaccine carriers, regardless of administration routes, should have certain common characteristics. They should maintain stability in given environments, be mucoadhesive, and have the ability to target specific tissues and cells.

Ferritin variants: inspirations for rationally designing protein nanocarriers

Ferritin, a natural iron storage protein, is endowed with a unique structure, the ability to self-assemble and excellent physicochemical properties. Beyond these, genetic manipulation can easily tune the structure and functions of ferritin nanocages, which further expands the biomedical applications of ferritin. Here, we focus on human H-ferritin, a recently discovered ligand of transferrin receptor 1, to review its derived variants and related structures and properties. We hope this review will provide new insights into how to rationally design versatile protein cage nanocarriers for effective disease treatment.

Tomato lectin-modified nanoemulsion-encapsulated MAGE1-HSP70/SEA complex protein vaccine: Targeting intestinal M cells following peroral administration

Vaccines administered orally enable the stimulation of both the mucous membrane and system immune responses. However, tumor vaccines, whose effective elements are antigen protein molecules or gene-encoding antigens, are hardly accustomed to the harsh gastrointestinal environment. Here, we explored an oral nanoecapsulated tumor vaccine complex to evaluate the anti-tumor effect. Tomato lectin (TL) was modified on the surface of a nanoemulsion (NE) composed of MAGE1-HSP70/SEA (MHS). C57BL/6 mice were immunized with NE (-), NE (MHS) and TL-NE (MHS) via po. or sc. administration. Additionally, the cellular immunocompetence was detected by the enzyme-linked immunospot assay and lactate dehydrogenase release assay. Serum antibody titers were analyzed using the enzyme-linked immuno sorbent assay. Next, the therapeutic and tumor challenge assays were performed. The TL-NE (MHS) particles were 20 ± 5 nm in diameter and could resist pepsin and trypsin digestion. The cellular immune responses elicited by TL-NE (MHS) perioral were stronger than those by TL-NE (MHS)-sc. (p < 0.05) when targeted to B16-MAGE1 tumor cells. The levels of MAGE-1 antibody induced by TL-NE (MHS) via the oral route was higher than control group (p < 0.05). The percentage of CD4+ and CD8+ T cells in TL-NE (MHS)-po. group was more than other groups (p < 0.05). Furthermore, oral TL-NE (M)HScould delay tumor growth and defer tumor occurrence and tumor recurrence after resection in mice challenged with B16-MAGE-1 tumor cells. The study suggested that the oral TL-NE (MHS) vaccine delivery system is feasible to improve the vaccine protection effect and may have broad application in cancer therapy.

Protein-based nanoparticles in cancer vaccine development

Peptide and protein-based cancer vaccines usually fail to elicit efficient immune responses against tumors. However, delivery of these peptides and proteins as components within caged protein nanoparticles has shown promising improvements in vaccine efficacy. Advantages of protein nanoparticles over other vaccine platforms include their highly organized structures and symmetry, biodegradability, ability to be specifically functionalized at three different interfaces (inside and outside the protein cage, and between subunits in macromolecular assembly), and ideal size for vaccine delivery. In this review, we discuss different classes of virus-like particles and caged protein nanoparticles that have been used as vehicles to transport and increase the interaction of cancer vaccine components with the immune system. We review the effectiveness of these protein nanoparticles towards inducing and elevating specific immune responses, which are needed to overcome the low immunogenicity of the tumor microenvironment.

Nanoparticle drug delivery systems: an excellent carrier for tumor peptide vaccines

In the past 40 years, the nanoparticle drug delivery system for tumor peptide vaccines has been widely studied which also reached a splendid result. Nanomaterial can enhance the targeting of vaccines, help vaccines enter the cells and trigger immune response by themselves. They also help in increasing cellular uptake, improving permeability and efficacy. Currently, several categories of nanopreparation, such as liposome, polymeric micelle, polymeric nanoparticle, gold nanoparticle and so on, are proved that they are appropriate for peptide vaccines. This review we discussed the possible mechanisms of nanomaterial's action on the regulation of immunological functions and several major applications of this advanced drug delivery system for tumor peptide vaccine.

Gas‑filled ultrasound microbubbles enhance the immunoactivity of the HSP70‑MAGEA1 fusion protein against MAGEA1‑expressing tumours

Advanced malignant melanoma is characterized by rapid development, poor prognosis and insensitivity to chemoradiotherapy. Immunotherapy has become one of the primary clinical treatments for malignant melanomas. In recent decades, identifying specific tumour antigens and the enhanced immunoactivity of tumour vaccines has become critical for engineering successful tumour vaccines. As a widely used vaccine carrier, heat shock protein 70 (HSP70) clearly increases the immunogenicity of tumour antigens, such as melanoma-associated antigen A1 (MAGEA1). Based on previous studies, gas-filled ultrasound microbubbles (MBs) were engineered to carry an HSP70-MAGEA1 fusion protein (FP). Following subcutaneous injection around the lymphatic nodes the FP was directly released into the lymph nodes under ultrasonic imaging. The results indicated that the microbubbles enhanced the immunoactivity of FPs more effectively than HSP70-MAGEA1 fusion alone. Additionally, HSP70-MAGEA1 delivered via microbubbles clearly inhibited and delayed the growth of MAGEA1-expressing B16 melanomas in mice and improved the survival times of these animals compared with the fusion protein alone. The results of the present study demonstrated that controlled MBs enhance the immunoactivity of FPs and also highlights novel, potential vaccine carriers and a new strategy for engineering controllable tumour vaccine designs.

Nanoparticle-based strategies for cancer immunotherapy and immunodiagnostics

Although recent successes in clinical trials are strengthening research focused on cancer immunology, the poor immunogenicity and off-target side effects of immunotherapeutics remain major challenges in translating these promising approaches to clinically feasible therapies in the treatment of a large range of tumors. Nanotechnology offers target-based approaches, which have shown significant improvements in the rapidly advancing field of cancer immunotherapy. Here, we first discuss the chemical and physical features of nanoparticulate systems that can be tuned to address the anticancer immune response, and then review recent, key examples of the exploited strategies, ranging from nanovaccines to NPs revising the tumor immunosuppressive microenvironment, up to immunotherapeutic multimodal NPs. Finally, the paper concludes by identifying the promising and outstanding challenges the field of emerging nanotechnologies is facing for cancer immunotherapy.

Enhanced antitumor immunity of nanoliposome-encapsulated heat shock protein 70 peptide complex derived from dendritic tumor fusion cells

Tumor-derived heat shock proteins peptide complex (HSP.PC-Tu) has been regarded as a promising antitumor agent. However, inadequate immunogenicity and low bioavailability limit the clinical uses of this agent. In a previous study, we first produced an improved HSP70.PC-based vaccine purified from dendritic cell (DC)-tumor fusion cells (HSP70.PC-Fc) which had increased immunogenicity due to enhanced antigenic tumor peptides compared to HSP70.PC-Tu. In order to increase the bioavailability of HSP70.PC-Fc, the peptide complex was encapsulated with nanoliposomes (NL-HSP70.PC-Fc) in this study. After encapsulation, the tumor immunogenicity was observed using various assays. It was demonstrated that the NL-HSP70.PC-Fc has acceptable stability. The in vivo antitumor immune response was increased with regard to T-cell activation, CTL response and tumor therapy efficiency compared to that of HSP70.PC-Fc. In addition, it was shown that DC maturation was improved by NL-HSP70.PC-Fc, which added to the antitumor immunity. The results obtained for NL-HSP70.PC-Fc, which improved immunogenicity and increases the bioavailability of HSP70.PC, may represent superior heat shock proteins (HSPs)-based tumor vaccines. Such vaccines deserve further investigation and may provide a preclinical rationale to translate findings into early phase trials for patients with breast tumors.

Oral delivery of nanoparticle-based vaccines

Most infectious diseases are caused by pathogenic infiltrations from the mucosal tract. Therefore, vaccines delivered to the mucosal tissues can mimic natural infections and provide protection at the first site of infection. Thus, mucosal, especially, oral delivery is becoming the most preferred mode of vaccination. However, oral vaccines have to overcome several barriers such as the extremely low pH of the stomach, the presence of proteolytic enzymes and bile salts as well as low permeability in the intestine. Several formulations based on nanoparticle strategies are currently being explored to prepare stable oral vaccine formulations. This review briefly discusses several molecular mechanisms involved in intestinal immune cell activation and various aspects of oral nanoparticle-based vaccine design that should be considered for improved mucosal and systemic immune responses.

Interleukin‑15: a potent adjuvant enhancing the efficacy of an autologous whole‑cell tumor vaccine against Lewis lung carcinoma

Lung cancer is a major cause of cancer‑associated mortality worldwide due to its limited response rate to current chemotherapy and radiation, thus immunotherapy is rapidly becoming the most promising approach. Although the highly specific tumor‑associated antigen of lung cancer has been found, autologous whole‑cell tumor vaccines remain indispensable in the development of therapeutic cancer vaccines. Interleukin (IL)‑15 is a T helper type 1 cytokine that has been demonstrated to have a marked antitumor immune response and the potential ability to reverse the host tolerance of tumor antigens in certain preclinical trials. In the present study, a cationic liposome encapsulating IL‑15 gene‑loaded plasmid acted as an adjuvant of an autologous whole‑cell tumor vaccine by subcutaneous injection. The combination immunotherapy resulted in significant inhibition of tumor growth without side effects in the preventive tumor inhibition and adoptive therapy study. Cytotoxic lymphocyte assay detection of the serum antigen and cytokines using an enzyme‑linked immunosorbent assay suggested that the IL‑15 gene can significantly improve the cellular immune response and humoral immune response provoked by autologous whole‑cell tumor vaccines. These results demonstrated that the IL‑15 gene was an effective adjuvant of autologous whole‑cell tumor vaccines against mouse lung cancer and may provide an attractive vaccine strategy for cancer immunotherapy.

Improvement of drug safety by the use of lipid-based nanocarriers

Drug toxicity is an important factor that contributes significantly to adverse drug events in current healthcare practice. Application of lipid-based nanocarriers in drug formulation is one approach to improve drug safety. Lipid-based delivery systems include micelles, liposomes, solid lipid nanoparticles, nanoemulsions and nanosuspensions. These carriers are generally composed of physiological lipids well tolerated by human body. Delivery of water-insoluble drugs in these formulations increases their solubility and stability in aqueous media and eliminates the need for toxic co-solvents or pH adjustment to solubilize hydrophobic drugs. Association or encapsulation of peptides/proteins within lipid-based carriers protects the labile biologics against enzymatic degradation, hence reducing the therapeutic dose required and risk of dose-dependent toxicity. Most importantly, lipid-based nanocarriers alter the pharmacokinetics and biodistribution of drugs through passive and active targeting, leading to increased drug accumulation at target sites while significantly decreasing non-specific distribution to other tissues. Furthermore, surface modification of these nanocarriers reduces immunogenicity of drug-carrier complexes, imparts stealth by preventing opsonization and removal by phagocytes and minimizes interaction with circulating blood components. In view of heightening attention on drug safety in patient treatment, lipid-based nanocarrier is therefore an important and promising option for formulation of pharmaceutical products to improve treatment safety and efficacy.

Nanocarrier possibilities for functional targeting of bioactive peptides and proteins: state-of-the-art

This review attempts to provide an updated compilation of studies reported in the literature pertaining to production of nanocarriers encasing peptides and/or proteins, in a way that helps the reader direct a bibliographic search and develop an integrated perspective of the subject. Highlights are given to bioactive proteins and peptides, with a special focus on those from dairy sources (including physicochemical characteristics and properties, and biopharmaceutical application possibilities of e.g. lactoferrin and glycomacropeptide), as well as to nanocarrier functional targeting. Features associated with micro- and (multiple) nanoemulsions, micellar systems, liposomes and solid lipid nanoparticles, together with biopharmaceutical considerations, are presented in the text in a systematic fashion.

Development and characterization of hyaluronic acid decorated PLGA nanoparticles for delivery of 5-fluorouracil

The present investigation was aimed to develop and explore the prospective of engineered PLGA nanoparticles as vehicles for targeted delivery of 5-fluorouracil (5-FU). Nanoparticles of 5-FU-loaded hyaluronic acid-poly(ethylene glycol)-poly(lactide-co-glycolide) (HA-PEG-PLGA-FU) copolymer were prepared and characterized by FTIR, NMR, transmission electron microscopy, particle size analysis, DSC, and X-ray diffractometer measurement studies. The nanoparticulate formulation was evaluated for in vitro release, hemolytic toxicity, and hematological toxicity. Cytotoxicity studies were performed on Ehrlich ascites tumor (EAT) cell lines using MTT cell proliferation assay. Biodistribution studies of 99m Tc labeled formulation were conducted on EAT-bearing mice. The in vivo tumor inhibition study was also performed after i.v. administration of HA-PEG-PLGA-FU nanoparticles. The HA conjugated formulation was found to be less hemolytic but more cytotoxic as compared to free drug. The hematological data suggested that HA-PEG-PLGA-FU formulation was less immunogenic compared to plain drug. The tissue distribution studies displayed that HA-PEG-PLGA-FU were able to deliver a higher concentration of 5-FU in the tumor mass. In addition, the HA-PEG-PLGA-FU nanoparticles reduced tumor volume significantly in comparison with 5-FU. Thus, it was concluded that the conjugation of HA imparts targetability to the formulation, and enhanced permeation and retention effect ruled out its access to the non-tumor tissues, at the same time favored selective entry in tumors, thereby reducing the side-effects both in vitro and in vivo.

Enhancing cellular cancer vaccines

Various strategies have been used to generate cellular cancer vaccines with the expectation that they will become an effective part of the overall management of cancer patients. However, with few notable exceptions, immunization has not resulted in significant long-term therapeutic benefits. Tumor growth has continued and patient survival has been at best only modestly prolonged. One possible explanation is that as only a small proportion of the constituents of malignant cells are "tumor specific" and the vast majority are the products of nonantigenic, normal "housekeeping" genes, the immune response in patients immunized with cellular cancer vaccines is not sufficient to result in tumor rejection. Here, we review and characterize various types of cellular cancer vaccines. In addition, in a mouse breast cancer model system, we describe a unique strategy designed to enrich cellular vaccines for cells that induce tumor immunity. Numerous advantages and disadvantages of cancer immunotherapy with cellular vaccines are also presented.

Nanoparticle delivery systems in cancer vaccines

Therapeutic strategies that involve the manipulation of the host's immune system are gaining momentum in cancer research. Antigen-loaded nanocarriers are capable of being actively taken up by antigen-presenting cells (APCs) and have shown promising potential in cancer immunotherapy by initiating a strong immunostimulatory cascade that results in potent antigen-specific immune responses against the cancer. Such carrier systems offer versatility in that they can simultaneously co-deliver adjuvants with the antigens to enhance APC activation and maturation. Furthermore, modifying the surface properties of these nanocarriers affords active targeting properties to APCs and/or enhanced accumulation in solid tumors. Here, we review some recent advances in these colloidal and particulate nanoscale systems designed for cancer immunotherapy and the potential for these systems to translate into clinical cancer vaccines.

Targeting the tumor microenvironment with anti-neu/anti-CD40 conjugated nanoparticles for the induction of antitumor immune responses

Clinical and preclinical data indicate that immunotherapeutic interventions could induce immune responses capable of controlling or retard the tumor growth. However, immunotherapies need to be further optimized. We hypothesized that a more effective strategy for tumor eradication is to directly target the tumor microenvironment in order to generate a proinflammatory response and induce a localized antitumor immune response capable of eliminating the tumor cells. Nanoparticles have been proven to be an effective delivery system. In these studies we evaluated conjugated anti-RNEU and anti-CD40 antibodies onto PLA-(poly dl-lactic acid)-biodegradable nanoparticles (PLA-NP) for the induction of antitumor immune responses. The anti-neu/anti-CD40-NP were functional in vitro recognizing RNEU(+) tumors and activating dendritic cells. The delivery of anti-neu/anti-CD40-NP but not anti-neu-NP or anti-CD40-NP induced an antitumor response resulting in complete tumor elimination and generation of protective memory responses. The anti-neu/anti-CD40-NP specifically activated an antitumor response against RNEU(+) tumors but not against RNEU(-) tumors. The antitumor immune responses correlate with the induction of a Th1-proinflammatory response, reduction in the number of Tregs within the tumor and activation of a specific cytotoxic response. These results indicate that anti-neu/anti-CD40-NP with immunomodulatory properties are safe and can be used effectively as cancer vaccines strategy for the specific induction of antitumor immune responses.