Anti-Tumoral Effect and Action Mechanism of Exosomes Derived From Toxoplasma gondii-Infected Dendritic Cells in Mice Colorectal Cancer

The Roles of Exosomes in Anti-Cancer Drugs

BACKGROUND

Cancer is an escalating global health issue, with rising incidence rates annually. Chemotherapy, a primary cancer treatment, often exhibits low tumor-targeting efficiency and severe side effects, limiting its effectiveness. Recent research indicates that exosomes, due to their immunogenicity and molecular delivery capabilities, hold significant potential as drug carriers for tumor treatment.

METHODS

This review summarizes the current status, powerful therapeutic potential, and challenges of using exosomes for the treatment of tumors.

RESULTS

Exosomes are crucial in tumor diagnosis, onset, and progression. To improve the efficacy of exosome-based treatments, researchers are exploring various biological, physical, and chemical approaches to engineer exosomes as a new nanomedicine translational therapy platform with broad and alterable therapeutic capabilities. Numerous clinical trials are currently underway investigating the safety and tolerability of exosomes carrying drugs to specific sites for the treatment of tumors.

CONCLUSIONS

Exosomes can be engineered as carriers to deliver therapeutic molecules to specific cells and tissues, offering a novel approach for disease treatment.

Drug Delivery Systems Based on Dendritic-Cell-Derived Exosomes

Exosomes, spherical lipid-bilayered particles secreted by cells, have recently emerged as a novel and highly promising drug delivery system, attracting extensive attention in the field of biomedical research. Dendritic-cell-derived exosomes (DC-Exos) possess surface protein and ligands characteristic of DC cells, such as functional MHC-I and MHC-II, CD80, CD86. These components play a crucial role in immune responses, facilitating antigen uptake, presentation, and the activation of antigen-specific CD4 and CD8 T cells. These properties make them striking and excellent drug delivery vehicles for use in various immune diseases and cancer therapy. This review summarizes and discusses the characteristics, current methods and types of drug loading of DC-Exos. Its surface modifications and application in disease treatment were also discussed, aiming to motivate the development of exosome-based theranostic nanoplatforms and nanotechnology for improved healthcare treatments.

Neospora caninum Inhibits Lewis Cancer and B16f10 Melanoma Lung Metastasis Development by Activating the Immune Response in Murine Models

Malignant tumors are prevalent with high mortality rates in humans, dogs, and cats. Some microorganisms have been shown to inhibit cancer progression. The objective of this study is to evaluate the inhibitory effects of Neospora caninum, a livestock parasite, on three different tumor models in C57BL/6 mice, including Lewis subcutaneous tumors, Lewis and B16F10 melanoma lung metastasis. The results showed that a sufficient amount of N. caninum tachyzoites can significantly inhibit the development of subcutaneous tumors and lung metastasis (P < 0.001), and induce more than 50% tumor cell death in Lewis subcutaneous tumors. N. caninum treatment can significantly increases the infiltration of macrophages, NK cells, and CD8+ T cells (P < 0.0001) in Lewis subcutaneous tumors detected by immunohistochemistry, and the percentage of these immunocytes in the spleen (P < 0.05) of mice bearing B16F10 melanoma metastasis detected by flow cytometry. And with these changes, the mRNA expression levels of IL-12, IFN-γ, IL-2, IL-10, TNF-α and PD-L1 in tumor microenvironment and IL-12, IFN-γ, IL-2 in spleen were also significantly increased (P < 0.05). Altogether, our results indicate that a sufficient amount N. caninum tachyzoites not only inhibits the growth of Lewis subcutaneous tumors, but inhibits the development of Lewis and B16F10 melanomas lung metastatic in mice by activating potent immune responses. N. caninum and its anti-tumor properties may be an effective anti-tumor tool.

Culture supernatant of Toxoplasma gondii tachyzoites inhibits the proliferation and metastasis of bladder cancer cells

Bladder cancer is the most common type of tumor in the urinary system and has a high incidence and mortality rate. Protozoan parasites have recently gained popularity as a research topic for cancer therapy. The present study aimed to evaluate the effect of T. gondii tachyzoite culture supernatants on bladder cancer cells. Bladder cancer 5637 cells were infected with two different genotypes of T. gondii tachyzoite culture supernatants, RH and ToxoDB#9. The effects of T. gondii tachyzoite culture supernatant on cell proliferation were detected using a Cell Counting Kit-8 assay. The effects on cell migration and invasion were evaluated using wound healing and Transwell assays. The effect on the apoptosis rate of the cells was assessed using a TUNEL assay, while the protein levels of Bax and Bcl-2 were analyzed by western blotting. The results indicated that the culture supernatant of T. gondii tachyzoites altered the morphology of bladder cancer 5637 cells, inhibited cell proliferation, reduced cell migration and invasion and promoted apoptosis. The ToxoDB#9-type experimental group showed higher efficacy than the RH-type experimental group in inhibiting bladder cancer cell proliferation, reducing cell migration and invasion and promoting apoptosis. These results indicated that the culture supernatant of T. gondii tachyzoites could be a promising therapeutic agent for the treatment of bladder cancer.

Toxoplasma gondii-Derived Exosomes: A Potential Immunostimulant and Delivery System for Tumor Immunotherapy Superior to Toxoplasma gondii

Immunotherapies such as immune checkpoint blockade (ICB) therapy and chimeric antigen receptor T-cell (CAR-T) therapy have ushered in a new era of tumor treatment. However, most patients do not benefit from immunotherapy due to limitations such as narrow indications, low response rates, and high rates of adverse effects. Toxoplasma gondii (T. gondii), a specialized intracellular protozoan, can modulate host immune responses by inhibiting or stimulating cytokines. The ability of T. gondii to enhance an organism's immune response was found to have a direct anti-tumor effect and enhance the sensitivity of patients with tumors to ICB therapy. However, the application of T. gondii for tumor therapy faces several challenges, such as biosafety concerns. Exosomes, a subtype of extracellular vesicle that contains active components such as proteins, nucleic acids, and lipids, have become effective therapeutic tools for various diseases, including tumors. Parasites, such as T. gondii, mediate the communication of pathogens with immune cells and modulate host cellular immune responses through exosomes. Growing evidence indicates that T. gondii-derived exosomes mediate communication between pathogens and immune cells, modulate host immune responses, and have great potential as new tools for tumor therapy. In this review, we highlight recent advances in isolation and identification techniques, profiling analysis, host immunomodulatory mechanisms, and the role of T. gondii-derived exosomes in tumor immunotherapy. Additionally, we emphasize the potential of T. gondii-derived exosomes as delivery platform to enhance anti-tumor efficacy in combination with other therapies. This review proposes that T. gondii-derived exosomes may serve as a novel tool for tumor immunotherapy owing to their ability to activate host immune function and properties such as high modifiability, stability, and low toxicity. This work will assist in promoting the application of parasite exosomes in tumor therapy.

Parasites revive hope for cancer therapy

Parasites have attained a life-long stigma of being detrimental organisms with deleterious outcomes. Yet, recently, a creditable twist was verified that can dramatically change our perception of those parasites from being a source of misery to millions of people to a useful anti-cancerous tool. Various parasites have shown promise to combat cancer in different experimental models, including colorectal, lung, and breast cancers, among others. Helminths and protozoan parasites, as well as their derivatives such as Echinococcus granulosus protein KI-1, Toxoplasma gondii GRA15II, and Trypanosoma cruzi calreticulin, have demonstrated the ability to inhibit tumor growth, angiogenesis, and metastasis. This article provides an overview of the literature on various cancer types that have shown promising responses to parasite therapy in both in vitro and in vivo animal studies. Parasites have shown anti-neoplastic activity through a variety of mechanisms that collectively contribute to their anti-cancer properties. These include immunomodulation, inhibition of angiogenesis, and molecular mimicry with cancer cells. This review article sheds light on this intriguing emerging field and emphasizes the value of collaborative multidisciplinary research projects with funding agencies and pharmaceutical companies. Thus, these strategies would secure continuous exploration of this new avenue and accelerate the advancement of cancer therapy research. Although experimental studies are heavily conducted by leaps and bounds, further steps are definitely lagging. Upgrading research from the experimental level to the clinical trial would be a wise progression toward efficient exploitation of the anti-neoplastic capabilities of parasites, ultimately saving countless lives.

Multiomics and single-cell sequencings reveal the specific biological characteristics of low Ki-67 triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) displays high heterogeneity. The majority of TNBC cases are characterized by high Ki-67 expression. TNBC with low Ki-67 expression accounts for only a small fraction of cases and has been relatively less studied.

Methods

This study analyzed a large single-center multiomics TNBC data set, combined with a single-cell data set. The clinical, genomic, and metabolic characteristics of patients with low Ki-67 TNBC were analyzed.

Results

The clinical and pathological characteristics were analyzed in 2217 TNBC patients. Low Ki-67 TNBC was associated with a higher patient age at diagnosis, a lower proportion of invasive ductal carcinoma, increased alterations in the PI3K-AKT-mTOR pathway, upregulated lipid metabolism pathways, and enhanced infiltration of M2 macrophages. High Ki-67 TNBC exhibited a higher prevalence of TP53 gene mutations, elevated nucleotide metabolism, and increased infiltration of M1 macrophages.

Conclusions

We identified specific genomic and metabolic characteristics unique to low Ki-67 TNBC, which have implications for the development of precision therapies and patient stratification strategies.

Parasite-enhanced immunotherapy: transforming the "cold" tumors to "hot" battlefields

Immunotherapy has emerged as a highly effective treatment for various tumors. However, the variable response rates associated with current immunotherapies often restrict their beneficial impact on a subset of patients. Therefore, more effective treatment approaches that can broaden the scope of therapeutic benefits to a larger patient population are urgently needed. Studies have shown that some parasites and their products, for example, Plasmodium, Toxoplasma, Trypanosoma, and Echinococcus, can effectively transform "cold" tumors into "hot" battlefields and reshape the tumor microenvironment, thereby stimulating innate and adaptive antitumor immune responses. These parasitic infections not only achieve the functional reversal of innate immune cells, such as neutrophils, macrophages, myeloid-derived suppressor cells, regulatory T cells, and dendritic cells, in tumors but also successfully activate CD4+/CD8+ T cells and even B cells to produce antibodies, ultimately resulting in an antitumor-specific immune response and antibody-dependent cellular cytotoxicity. Animal studies have confirmed these findings. This review discusses the abovementioned content and the challenges faced in the future clinical application of antitumor treatment strategies based on parasitic infections. With the potential of these parasites and their byproducts to function as anticancer agents, we anticipate that further investigations in this field could yield significant advancements in cancer treatment.

Extracellular vesicles mediated gastric cancer immune response: tumor cell death or immune escape?

Gastric cancer (GC) is a major global health issue, being the fifth most prevalent cancer and the third highest contributor to cancer-related deaths. Although treatment strategies for GC have diversified, the prognosis for advanced GC remains poor. Hence, there is a critical need to explore new directions for GC treatment to enhance diagnosis, treatment, and patient prognosis. Extracellular vesicles (EVs) have emerged as key players in tumor development and progression. Different sources of EVs carry different molecules, resulting in distinct biological functions. For instance, tumor-derived EVs can promote tumor cell proliferation, alter the tumor microenvironment and immune response, while EVs derived from immune cells carry molecules that regulate immune function and possess tumor-killing capabilities. Numerous studies have demonstrated the crucial role of EVs in the development, immune escape, and immune microenvironment remodeling in GC. In this review, we discuss the role of GC-derived EVs in immune microenvironment remodeling and EVs derived from immune cells in GC development. Furthermore, we provide an overview of the potential uses of EVs in immunotherapy for GC.

Extracellular Microvesicles Modified with Arginine-Rich Peptides for Active Macropinocytosis Induction and Delivery of Therapeutic Molecules

Extracellular vesicles (EVs), including exosomes and microvesicles (MVs), transfer bioactive molecules from donor to recipient cells in various pathophysiological settings, thereby mediating intercellular communication. Despite their significant roles in extracellular signaling, the cellular uptake mechanisms of different EV subpopulations remain unknown. In particular, plasma membrane-derived MVs are larger vesicles (100 nm to 1 μm in diameter) and may serve as efficient molecular delivery systems due to their large capacity; however, because of size limitations, receptor-mediated endocytosis is considered an inefficient means for cellular MV uptake. This study demonstrated that macropinocytosis (lamellipodia formation and plasma membrane ruffling, causing the engulfment of large fluid volumes outside cells) can enhance cellular MV uptake. We developed experimental techniques to induce macropinocytosis-mediated MV uptake by modifying MV membranes with arginine-rich cell-penetrating peptides for the intracellular delivery of therapeutic molecules.

A novel enemy of cancer: recent investigations into protozoan anti-tumor properties

Cancer remains a significant global health issue, despite advances in screening and treatment. While existing tumor treatment protocols such as surgery, chemotherapy, radiotherapy, targeted therapy, and immunotherapy have proven effective in enhancing the prognosis for some patients, these treatments do not benefit all patients. Consequently, certain types of cancer continue to exhibit a relatively low 5-year survival rate. Therefore, the pursuit of novel tumor intervention strategies may help improve the current effectiveness of tumor treatment. Over the past few decades, numerous species of protozoa and their components have exhibited anti-tumor potential via immune and non-immune mechanisms. This discovery introduces a new research direction for the development of new and effective cancer treatments. Through in vitro experiments and studies involving tumor-bearing mice, the anti-tumor ability of Toxoplasma gondii, Plasmodium, Trypanosoma cruzi, and other protozoa have unveiled diverse mechanisms by which protozoa combat cancer, demonstrating encouraging prospects for their application. In this review, we summarize the anti-tumor ability and anti-tumor mechanisms of various protozoa and explore the potential for their clinical development and application.

Toxoplasma gondii infection possibly reverses host immunosuppression to restrain tumor growth

Tumor cells can successfully escape the host immune attack by inducing the production of immunosuppressive cells and molecules, leading to an ineffective tumor treatment and poor prognosis. Although immunotherapies have improved the survival rate of cancer patients in recent years, more effective drugs and therapies still need to be developed. As an intracellular parasite, Toxoplasma gondii can trigger a strong Th1 immune response in host cells, including upregulating the expression of interleukin-12 (IL-12) and interferon-γ (IFN-γ). Non-replicating uracil auxotrophic strains of T. gondii were used to safely reverse the immunosuppression manipulated by the tumor microenvironment. In addition to the whole lysate antigens, T. gondii-secreted effectors, including Toxoplasma profilin, rhoptry proteins (ROPs), and dense granule antigens (GRAs), are involved in arousing the host’s antigen presentation system to suppress tumors. When T. gondii infection relieves immunosuppression, tumor-related myeloid cells, including macrophages and dendritic cells (DCs), are transformed into immunostimulatory phenotypes, showing a powerful Th1 immune response mediated by CD8⁺ T cells. Afterwards, they target and kill the tumor cells, and ultimately reduce the size and weight of tumor tissues. This article reviews the latest applications of T. gondii in tumor therapy, including the activation of cellular immunity and the related signal pathways, which will help us understand why T. gondii infection can restrain tumor growth.