Cross-Presentation of Tumor Antigens Is Ruled by Synaptic Transfer of Vesicles among Dendritic Cell Subsets

Clinical advances and challenges associated with TCR-T cell therapy for cancer treatment

Background

T cell receptor (TCR)-T cell therapy is an innovative form of cancer immunotherapy that genetically modifies patients' T cells to target and destroy cancer cells. However, the current status of clinical trials of TCR-T cell therapy for the treatment of cancer remains unclear. This study aimed to comprehensively analyze the registration trials related to TCR-T cell therapy for the treatment of cancer.

Methods

A comprehensive search was conducted in the Trialtrove database for all clinical trials related to TCR-T cell therapy registered by August 1, 2024. Inclusion criteria focused on trials targeting TCR-T cell therapy for oncology, and excluded observational studies and incomplete data. Statistical analysis was performed on key trial characteristics, with between-group comparisons utilizing chi-square or Fisher's exact tests.

Results

Analysis of 174 eligible clinical trials revealed that TCR-T cell therapy exhibits significant efficacy across various tumor types, particularly in refractory hematologic malignancies and certain solid tumors. Additionally, combining TCR-T cell therapy with other immunotherapies enhanced these anti-tumor effects.

Conclusion

TCR-T cell therapy holds substantial promise for cancer treatment. Future research should focus on optimizing treatment protocols, enhancing efficacy, and minimizing prices to fully realize the potential of this therapy.

Extracellular vesicle-mediated crosstalk in tumor microenvironment dominates tumor fate

The tumor microenvironment (TME) is a complex and heterogeneous system containing various cells cooperating and competing with each other. Extracellular vesicles (EVs) differing in form and content are important intercellular communication mediators in the TME. Previous studies have focused on the cargoes within EVs rather than on the donors from which they originate and the recipient cells that exert their effects. Therefore, we provide here a detailed overview of the important roles of EVs in shaping tumor fate, highlighting their various mechanisms of intercellular dialog within the TME. We evaluate recent advances and also raise unresolved challenges to provide new ideas for clinical treatment strategies using EVs.

Insights into therapeutic peptides in the cancer-immunity cycle: Update and challenges

Immunotherapies hold immense potential for achieving durable potency and long-term survival opportunities in cancer therapy. As vital biological mediators, peptides with high tissue penetration and superior selectivity offer significant promise for enhancing cancer immunotherapies (CITs). However, physicochemical peptide features such as conformation and stability pose challenges to their on-target efficacy. This review provides a comprehensive overview of recent advancements in therapeutic peptides targeting key steps of the cancer-immunity cycle (CIC), including tumor antigen presentation, immune cell regulation, and immune checkpoint signaling. Particular attention is given to the opportunities and challenges associated with these peptides in boosting CIC within the context of clinical progress. Furthermore, possible future developments in this field are also discussed to provide insights into emerging CITs with robust efficacy and safety profiles.

Role of Extracellular Vesicles in Immunity and Host Defense

Extracellular vesicles (EVs) are membrane-bound structures released by cells and have become significant players in immune system functioning, primarily by facilitating cell-to-cell communication. Immune cells like neutrophils and dendritic cells release EVs containing bioactive molecules that modulate chemotaxis, activate immune cells, and induce inflammation. EVs also contribute to antigen presentation, lymphocyte activation, and immune tolerance. Moreover, EVs play pivotal roles in antimicrobial host defense. They deliver microbial antigens to antigen-presenting cells (APCs), triggering immune responses, or act as decoys to neutralize virulence factors and toxins. This review discusses host and microbial EVs' multifaceted roles in innate and adaptive immunity, highlighting their involvement in immune cell development, antigen presentation, and antimicrobial responses.

In Situ Vaccination Following Intratumoral Injection of IL2 and Poly-l-lysine/Iron Oxide/CpG Nanoparticles to a Radiated Tumor Site

The in situ vaccine effect of radiation therapy (RT) has been shown to be limited in both preclinical and clinical settings, possibly due to the inadequacy of RT alone to stimulate in situ vaccination in immunologically "cold" tumor microenvironments (TMEs) and the mixed effects of RT in promoting tumor infiltration of both effector and suppressor immune cells. To address these limitations, we combined intratumoral injection of the radiated site with IL2 and a multifunctional nanoparticle (PIC). The local injection of these agents produced a cooperative effect that favorably immunomodulated the irradiated TME, enhancing the activation of tumor-infiltrating T cells and improving systemic anti-tumor T cell immunity. In syngeneic murine tumor models, the PIC+IL2+RT combination significantly improved the tumor response, surpassing the single or dual combinations of these treatments. Furthermore, this treatment led to the activation of tumor-specific immune memory and improved abscopal effects. Our findings suggest that this strategy can be used to augment the in situ vaccine effect of RT in clinical settings.

Extracellular vesicles as next generation immunotherapeutics

Extracellular vesicles (EVs) function as a mode of intercellular communication and molecular transfer to elicit diverse biological/functional response. Accumulating evidence has highlighted that EVs from immune, tumour, stromal cells and even bacteria and parasites mediate the communication of various immune cell types to dynamically regulate host immune response. EVs have an innate capacity to evade recognition, transport and transfer functional components to target cells, with subsequent removal by the immune system, where the immunological activities of EVs impact immunoregulation including modulation of antigen presentation and cross-dressing, immune activation, immune suppression, and immune surveillance, impacting the tumour immune microenvironment. In this review, we outline the recent progress of EVs in immunorecognition and therapeutic intervention in cancer, including vaccine and targeted drug delivery and summarise their utility towards clinical translation. We highlight the strategies where EVs (natural and engineered) are being employed as a therapeutic approach for immunogenicity, tumoricidal function, and vaccine development, termed immuno-EVs. With seminal studies providing significant progress in the sequential development of engineered EVs as therapeutic anti-tumour platforms, we now require direct assessment to tune and improve the efficacy of resulting immune responses - essential in their translation into the clinic. We believe such a review could strengthen our understanding of the progress in EV immunobiology and facilitate advances in engineering EVs for the development of novel EV-based immunotherapeutics as a platform for cancer treatment.

Antigen transfer and its effect on vaccine-induced immune amplification and tolerance

Antigen transfer refers to the process of intercellular information exchange, where antigenic components including nucleic acids, antigen proteins/peptides and peptide-major histocompatibility complexes (p-MHCs) are transmitted from donor cells to recipient cells at the thymus, secondary lymphoid organs (SLOs), intestine, allergic sites, allografts, pathological lesions and vaccine injection sites via trogocytosis, gap junctions, tunnel nanotubes (TNTs), or extracellular vesicles (EVs). In the context of vaccine inoculation, antigen transfer is manipulated by the vaccine type and administration route, which consequently influences, even alters the immunological outcome, i.e., immune amplification and tolerance. Mainly focused on dendritic cells (DCs)-based antigen receptors, this review systematically introduces the biological process, molecular basis and clinical manifestation of antigen transfer.

The roles of extracellular vesicles in the immune system

The twenty-first century has witnessed major developments in the field of extracellular vesicle (EV) research, including significant steps towards defining standard criteria for the separation and detection of EVs. The recent recognition that EVs have the potential to function as biomarkers or as therapeutic tools has attracted even greater attention to their study. With this progress in mind, an updated comprehensive overview of the roles of EVs in the immune system is timely. This Review summarizes the roles of EVs in basic processes of innate and adaptive immunity, including inflammation, antigen presentation, and the development and activation of B cells and T cells. It also highlights key progress related to deciphering the roles of EVs in antimicrobial defence and in allergic, autoimmune and antitumour immune responses. It ends with a focus on the relevance of EVs to immunotherapy and vaccination, drawing attention to ongoing or recently completed clinical trials that aim to harness the therapeutic potential of EVs.

Saga of monokines in shaping tumour-immune microenvironment: Origin to execution

Cellular communication mediated by cytokines is an important mechanism dictating immune responses, their cross talk and final immune output. Cytokines play a major role in dictating the immune outcome to cancer by regulating the events of development, differentiation and activation of innate immune cells. Cytokines are pleiotropic in nature, hence understanding their role individually or as member of network cytokines is critical to delineate their role in tumour immunity. Tumour systemically manipulates the immune system to evade and escape immune recognition for their uncontrollable growth and metastasis. The developing tumour comprise a large and diverse set of myeloid cells which are vulnerable to manipulation by the tumour-microenvironment. The innate immune cells of the monocytic lineage skew the fate of the adaptive immune cells and thus dictating cancer elimination or progression. Targeting cells at tumour cite is preposterous owing to their tight network, poor reach and abundance of immunosuppressive mechanisms. Monocytic lineage-derived cytokines (monokines) play crucial role in tumour regression or progression by either directly killing the tumour cells with TNFα or promoting its growth by TGFβ. In addition, the monokines like IL-12, IL-1β, IL-6, IL-10 and TGFβ direct the adaptive immune cells to secrete anti-tumour cytokines, TNFα, IFNγ, perforin and granzyme or pro-tumour cytokines, IL-10 and TGFβ. In this review, we elucidate the roles of monokines in dictating the fate of tumour by regulating responses at various stages of generation, differentiation and activation of immune cells along with the extensive cross talk. We have attempted to delineate the synergy and antagonism of major monokines among themselves or with tumour-derived or adaptive immune cytokines. The review provides an update on the possibilities of placing monokines to potential practical use as cytokine therapy against cancer.

Universal immunotherapeutic strategy for hepatocellular carcinoma with exosome vaccines that engage adaptive and innate immune responses

Background

Personalized immunotherapy utilizing cancer vaccines tailored to the tumors of individual patients holds promise for tumors with high genetic heterogeneity, potentially enabling eradication of the tumor in its entirety.

Methods

Here, we demonstrate a general strategy for biological nanovaccines that trigger tailored tumor-specific immune responses for hepatocellular carcinoma (HCC). Dendritic cell (DC)-derived exosomes (DEX) are painted with a HCC-targeting peptide (P47-P), an α-fetoprotein epitope (AFP212-A2) and a functional domain of high mobility group nucleosome-binding protein 1 (N1ND-N), an immunoadjuvant for DC recruitment and activation, via an exosomal anchor peptide to form a “trigger” DEX vaccine (DEX_P&A2&N).

Results

DEX_P&A2&N specifically promoted recruitment, accumulation and activation of DCs in mice with orthotopic HCC tumor, resulting in enhanced cross-presentation of tumor neoantigens and de novo T cell response. DEX_P&A2&N elicited significant tumor retardation and tumor-specific immune responses in HCC mice with large tumor burdens. Importantly, tumor eradication was achieved in orthotopic HCC mice when antigenic AFP peptide was replaced with the full-length AFP (A) to form DEX_P&A&N. Supplementation of Fms-related tyrosine kinase 3 ligand greatly augmented the antitumor immunity of DEX_P&A&N by increasing immunological memory against tumor re-challenge in orthotopic HCC mice. Depletion of T cells, cross-presenting DCs and other innate immune cells abrogated the functionality of DEX_P&A&N.

Conclusions

These findings demonstrate the capacity of universal DEX vaccines to induce tumor-specific immune responses by triggering an immune response tailored to the tumors of each individual, thus presenting a generalizable approach for personalized immunotherapy of HCC, by extension of other tumors, without the need to identify tumor antigens.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01266-8.

Survival Advantage Following TAG-72 Antigen-Directed Cancer Surgery in Patients With Colorectal Carcinoma: Proposed Mechanisms of Action

Patients with colorectal carcinoma (CRC) continue to have variable clinical outcomes despite undergoing the same surgical procedure with curative intent and having the same pathologic and clinical stage. This problem suggests the need for better techniques to assess the extent of disease during surgery. We began to address this problem 35 years ago by injecting patients with either primary or recurrent CRC with 125I-labeled murine monoclonal antibodies against the tumor-associated glycoprotein-72 (TAG-72) and using a handheld gamma-detecting probe (HGDP) for intraoperative detection and removal of radioactive, i.e., TAG-72-positive, tissue. Data from these studies demonstrated a significant difference in overall survival data (p < 0.005 or better) when no TAG-72-positive tissue remained compared to when TAG-72-positive tissue remained at the completion of surgery. Recent publications indicate that aberrant glycosylation of mucins and their critical role in suppressing tumor-associated immune response help to explain the cellular mechanisms underlying our results. We propose that monoclonal antibodies to TAG-72 recognize and bind to antigenic epitopes on mucins that suppress the tumor-associated immune response in both the tumor and tumor-draining lymph nodes. Complete surgical removal of all TAG-72-positive tissue serves to reverse the escape phase of immunoediting, allowing a resetting of this response that leads to improved overall survival of the patients with either primary or recurrent CRC. Thus, the status of TAG-72 positivity after resection has a significant impact on patient survival.

Strategy and clinical application of up-regulating cross presentation by DCs in anti-tumor therapy

The cross presentation of exogenous antigen (Ag) by dendritic cells (DCs) facilitates a diversified mode of T-cell activation, orchestrates specific humoral and cellular immunity, and contributes to an efficient anti-tumor immune response. DCs-mediated cross presentation is subject to both intrinsic and extrinsic factors, including the homing and phenotype of DCs, the spatiotemporal trafficking and degradation kinetics of Ag, and multiple microenvironmental clues, with many details largely unexplored. Here, we systemically review the current mechanistic understanding and regulation strategies of cross presentation by heterogeneous DC populations. We also provide insights into the future exploitation of DCs cross presentation for a better clinical efficacy in anti-tumor therapy.

MMP2 and TLRs modulate immune responses in the tumor microenvironment

The presence of an immunosuppressive tumor microenvironment is a major obstacle in the success of cancer immunotherapies. Because extracellular matrix components can shape the microenvironment, we investigated the role of matrix metalloproteinase 2 (MMP2) in melanoma tumorigenesis. We found that MMP2 signals proinflammatory pathways on antigen presenting cells, and this requires both TLR2 and TLR4. B16 melanoma cells that express MMP2 at baseline have slower kinetics in Tlr2^–/–Tlr4^–/– mice, implicating MMP2 in promoting tumor growth. Indeed, Mmp2 overexpression in B16 cells potentiated rapid tumor growth, which was accompanied by reduced intratumoral cytolytic cells and increased M2 macrophages. In contrast, knockdown of Mmp2 slowed tumor growth and enhanced T cell proliferation and NK cell recruitment. Finally, we found that these effects of MMP2 are mediated through dysfunctional DC–T cell cross-talk as they are lost in Batf3^–/– and Rag2^–/– mice. These findings provide insights into the detrimental role of endogenous alarmins like MMP2 in modulating immune responses in the tumor microenvironment.

Roles of exosomes in cancer chemotherapy resistance, progression, metastasis and immunity, and their clinical applications (Review)

Exosomes are a type of vesicle that are secreted by cells, with a diameter of 40-100 nm, and that appear as a cystic shape under an electron microscope. Exosome cargo includes a variety of biologically active substances such as non-coding RNA, lipids and small molecule proteins. Exosomes can be taken up by neighboring cells upon secretion or by distant cells within the circulatory system, affecting gene expression of the recipient cells. The present review discusses the formation and secretion of exosomes, and how they can remodel the tumor microenvironment, enhancing cancer cell chemotherapy resistance and tumor progression. Exosome-mediated induction of tumor metastasis is also highlighted. More importantly, the review discusses the manner in which exosomes can change the metabolism of cancer cells and the immune system, which may help to devise novel therapeutic approaches for cancer treatment. With the development of nanotechnology, exosomes can also be used as biomarkers and for the delivery of chemical drugs, serving as a tool to diagnose and treat cancer.

Dendritic Cells: Behind the Scenes of T-Cell Infiltration into the Tumor Microenvironment

Tumor-infiltrating CD8+ T cells have been shown to play a crucial role in controlling tumor progression. However, the recruitment and activation of these immune cells at the tumor site are strictly dependent on several factors, including the presence of dendritic cells (DCs), the main orchestrators of the antitumor immune responses. Among the various DC subsets, the role of cDC1s has been demonstrated in several preclinical experimental mouse models. In addition, the high density of tumor-infiltrating cDC1s has been associated with improved survival in many cancer patients. The ability of cDC1s to modulate antitumor activity depends on their interaction with other immune populations, such as NK cells. This evidence has led to the development of new strategies aimed at increasing the abundance and activity of cDC1s in tumors, thus providing attractive new avenues to enhance antitumor immunity for both established and novel anticancer immunotherapies. In this review, we provide an overview of the various subsets of DCs, focusing in particular on the role of cDC1s, their ability to interact with other intratumoral immune cells, and their prognostic significance on solid tumors. Finally, we outline key therapeutic strategies that promote the immunogenic functions of DCs in cancer immunotherapy.