Immuno-therapeutic potential of Schistosoma mansoni and Trichinella spiralis antigens in a murine model of colon cancer

Trichinella spiralis Larval Extract as a Biological Anti-Tumor Therapy in a Murine Model of Ehrlich Solid Carcinoma

Trichinella spiralis (T. spiralis) is an immunomodulating parasite that can adversely affect tumor growth and extend host lifespan. The aim of this study was to elucidate the mechanisms by which T. spiralis larval antigens achieve this effect using Ehrlich solid carcinoma (ESC) murine model. Assessment was done by histopathological and immunohistochemical analysis of caspase-3, TNF-α, Ki-67 and CD31. Additionally, Bcl2 and Bcl2-associated protein X (Bax) relative gene expression was assessed by molecular analysis for studying the effect of T. spiralis crude larval extract (CLE) antigen on tumor necrosis, apoptosis, cell proliferation and angiogenesis. We found that both T. spiralis infection and CLE caused a decrease in the areas of necrosis in ESC. Moreover, they led to increased apoptosis through activation of caspase-3, up-regulation of pro-apoptotic gene, Bax and down-regulation of anti-apoptotic gene, Bcl2. Also, T. spiralis infection and CLE diminished ESC proliferation, as evidenced by decreasing Ki-67. T. spiralis infection and CLE were able to suppress the development of ESC by inhibiting tumor proliferation, inducing apoptosis and decreasing tumor necrosis, with subsequent decrease in tumor metastasis. T. spiralis CLE antigen may be considered as a promising complementary immunotherapeutic agent in the treatment of cancer.

Parasites as potential targets for cancer immunotherapy

Parasites and cancers have some common antigens. Much scientific evidence in the human population, animal models, and in vitro experiments exhibit that parasites have significant anti-cancer effects. The larval stage of the tapeworm Echinococcus granulosus, Toxoplasma gondii, Trypanosoma cruzy, Plasmodium's, and Trichinella spiralis are among the parasites that have been subjects of anti-cancer research in the last decades. Anti-tumor effects of parasites may be due to the direct impact of the parasites per se or indirectly due to the immune response raised against common antigens between malignant cells and parasites. This manuscript reviews the anti-cancer effects of parasites and possible mechanisms of these effects. Options for using parasites or their antigens for cancer treatment in the future have been discussed.

Shedding light on a mysterious link between Toxoplasma Gondii and cancer: A review

The ongoing conflict regarding the affiliation of Toxoplasma gondii to cancer; whether an inducer or a suppressor needs to be resolved. Human epidemiological studies oscillate without attaining a firm ground. Some studies confirmed the detection of high seroprevalence of anti-Toxoplasma antibodies in different cancer patients without further justification whether being causation, co-incidences, or part of opportunistic infections. Others reported a state of resistance to cancer accompanying low titer of anti-Toxoplasma antibody. Worthwhile, preclinical experimental work confirmed the antineoplastic potency of Toxoplasma. Thus, further investigational research is essential to validate the potential application of Toxoplasma as a promising cancer immunotherapeutic vaccine candidate. In this paper, we present a review of this issue by examining epidemiological and preclinical experimental studies that explored the linkage between Toxoplasma gondii and cancer<i.></i> We consider this review an important step towards shedding a light on this mysterious link and a stepping-stone for potential research work addressing Toxoplasma as a cancer suppressor rather than a cancer inducer.

Experimental Murine Models for Colorectal Cancer Research

Colorectal cancer (CRC) is the third most prevalent malignancy worldwide and in both sexes. Numerous animal models for CRC have been established to study its biology, namely carcinogen-induced models (CIMs) and genetically engineered mouse models (GEMMs). CIMs are valuable for assessing colitis-related carcinogenesis and studying chemoprevention. On the other hand, CRC GEMMs have proven to be useful for evaluating the tumor microenvironment and systemic immune responses, which have contributed to the discovery of novel therapeutic approaches. Although metastatic disease can be induced by orthotopic injection of CRC cell lines, the resulting models are not representative of the full genetic diversity of the disease due to the limited number of cell lines suitable for this purpose. On the other hand, patient-derived xenografts (PDX) are the most reliable for preclinical drug development due to their ability to retain pathological and molecular characteristics. In this review, the authors discuss the various murine CRC models with a focus on their clinical relevance, benefits, and drawbacks. From all models discussed, murine CRC models will continue to be an important tool in advancing our understanding and treatment of this disease, but additional research is required to find a model that can correctly reflect the pathophysiology of CRC.

Prophylactic antineoplastic activity of Toxoplasma gondii RH derived antigen against ehrlich solid carcinoma with evidence of shared antigens by comparative immunoblotting

BACKGROUND

With cancer cases escalation, an urgent request to develop novel combating strategies arise. Pathogen-based cancer-immunotherapy is getting more consideration. Autoclaved parasitic antigens seem promising candidates, taking steadily their first steps. Our aim was to examine the prophylactic antineoplastic activity of autoclaved Toxoplasma vaccine (ATV) and to test for the shared antigen theory between Toxoplasma gondii and cancer cells.

METHODS

Mice were immunized with ATV followed by Ehrlich solid carcinoma (ESC) inoculation. Tumor weight, volume, histopathology, and immunohistochemistry for CD8⁺ T cells, Treg cells and VEGF were assessed. In addition, the proposed shared antigen theory between parasites and cancer was also verified using SDS-PAGE and immunoblotting.

RESULTS

Results revealed powerful prophylactic activity of ATV with 13.3% inhibition of ESC incidence, significant reduction in tumor weight and volume in ATV vaccinated mice. Immunologically, significantly higher CD8⁺T cells and lower FOXP3⁺ Treg cells surrounded and infiltrated ESC in ATV immunized mice with higher CD8⁺T/Treg cells ratio and significant antiangiogenic effect. Moreover, SDS-PAGE and immunoblotting showed four shared bands between Ehrlich carcinoma and ATV of approximate molecular weights 60, 26, 22 and 12.5 KDa.

CONCLUSION

Exclusively, we demonstrated a prophylactic antineoplastic activity of autoclaved Toxoplasma vaccine against ESC. Moreover, to the best of our knowledge this is the first report highlighting the existence of cross-reactive antigens between Toxoplasma gondi parasite and cancer cells of Ehrlich carcinoma.

Toxoplasma gondii-derived antigen modifies tumor microenvironment of Ehrlich solid carcinoma murine model and enhances immunotherapeutic activity of cyclophosphamide

Pathogen-based cancer vaccine is a promising immunotherapeutic weapon to stimulate cancer immunosuppressive state. Toxoplasma gondii is a potent immunostimulant, and low-dose infection was linked to cancer resistance. Our goal was to evaluate the therapeutic antineoplastic activity of autoclaved Toxoplasma vaccine (ATV) against Ehrlich solid carcinoma (ESC) in mice in reference to and in combination with low-dose cyclophosphamide (CP), a cancer immunomodulator. Mice inoculation with ESC was followed by applying different treatment modalities including ATV, CP, and CP/ATV. We evaluated the impact of the different treatments on liver enzymes and pathology, tumor weight, volume, and histopathological changes. Using immunohistochemistry, we evaluated CD8⁺ T cell, FOXP3⁺ Treg, CD8⁺/Treg outside and inside ESC, and angiogenesis. Results showed significant tumor weights and volumes reduction with all treatments with 13.3% inhibition of tumor development upon combined CP/ATV use. Significant necrosis and fibrosis were noted in ESC by all treatments with improved hepatic functions versus non-treated control. Although ATV was almost equivalent to CP in tumor gross and histopathology, it promoted an immunostimulatory activity with significant Treg cells depletion outside ESC and CD8⁺ T cells infiltration inside ESC with higher CD8⁺ T/Treg ratio inside ESC superior to CP. Combined with CP, ATV exhibited significant synergistic immunotherapeutic and antiangiogenic action compared to either treatment alone with significant Kupffer cells hyperplasia and hypertrophy. Exclusively, therapeutic antineoplastic and antiangiogenic activity of ATV against ESC was verified that boosted CP immunomodulatory action which highlights a novel biological cancer immunotherapeutic vaccine candidate.

Anti-Tumor Effect of Protoscolex Hydatid Cyst Somatic Antigen on Inhibition Cell Growth of K562

BACKGROUND AND OBJECTIVE

Today, cancer is one of the most important causes of death in the world, and so far, many treatment methods have been used in this field. Immunotherapy is considered one of the newest developments in this science, and it is still being investigated in some forms in different cancers and with a variety of antigens as well. One of the subsets of cancer immunotherapy is its treatment using parasitic antigens. The present study evaluated the effect of using somatic antigens of protoscoleces of Echinococcus granulosus on K562 cancer cells.

METHODS

In this study, hydatid cysts' protoscolex antigens were extracted, purified, and added to K562 cancer cells at three concentrations (0.1, 1, and 2 mg/ml) and on three times (24, 48, and 72 h). The number of apoptotic cells was compared to the control flask. The antigen concentration of 2 mg/ml was used as a control sample to investigate its cytotoxic effect on the growth of healthy HFF3 cells. Annexin V and PI tests were also performed to differentiate apoptosis from necrosis.

RESULTS

In flasks treated with hydatid cyst protoscolex antigen, all three concentrations significantly reduced the growth of cancer cells compared with the control flask, and concentration 2 of crude antigen significantly caused the death of cancer cells. Furthermore, more cancer cells underwent apoptosis by increasing the time of exposure to the antigen. On the other hand, flow cytometry results also showed that the amount of apoptosis has increased compared to the control group. In fact, Protoscolex hydatid cyst somatic antigens induce programmed cell death in K562 cancer cells while not having a cytotoxic effect on normal cells.

CONCLUSION

Therefore, it is suggested to do more research on the anti-cancer and therapeutic properties of the antigens of this parasite.

Does Schistosoma Mansoni Facilitate Carcinogenesis?

Schistosomiasis is one of the most prominent parasite-induced infectious diseases, causing tremendous medical and socioeconomic problems. Current studies have reported on the spread of endemic regions and the fear of development of resistance against praziquantel, the only effective drug available. Among the Schistosoma species, only S. haematobium is classified as a Group 1 carcinogen (definitely cancerogenic to humans), causing squamous cell carcinoma of the bladder, whereas infection with S. mansoni is included in Group 3 of carcinogenic hazards to humans by the International Agency for Research on Cancer (IARC), indicating insufficient evidence to determine its carcinogenicity. Nevertheless, although S. mansoni has not been discussed as an organic carcinogen, the multiplicity of case reports, together with recent data from animal models and cell culture experiments, suggests that this parasite can predispose patients to or promote hepatic and colorectal cancer. In this review, we discuss the current data, with a focus on new developments regarding the association of S. mansoni infection with human cancer and the recently discovered biomolecular mechanisms by which S. mansoni may predispose patients to cancer development and carcinogenesis.

The Apoptotic Effect of Trichinella spiralis Infection Against Experimentally Induced Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC) is the sixth most common type of cancer. Prognosis of HCC remains unsatisfactory. Therefore, developing new therapeutic modalities is still mandatory. Tumor biotherapy is a novel concept developed as a therapeutic strategy for cancer treatment. There is a similarity between the regulatory mechanism of Trichinella spiralis nurse cell formation and tumor cell apoptosis signal regulation.

OBJECTIVES

Induction of apoptosis by T. spiralis can represent a new strategy for tumor treatment.

METHODS

Experimental animals were divided in four groups; negative control (GI), T. spiralis infected (GII), induced HCC (GIII) and HCC then infected with T. spiralis (GIV). The apoptotic effect of T. spiralis infection was assessed by histopathological and immunohistochemical staining of B-cell lymphoma 2 (Bcl-2).

RESULTS

We found higher survival rate of rats and decreased weight of their livers with no nodules in HCC- T. spiralis group as compared to HCC group. Improvement of the dysplastic changes and increased apoptotic bodies which was confirmed by decreased expression of Bcl-2 reported in HCC- T. spiralis group.

CONCLUSION

Trichinella-induced apoptosis can be a contributing mechanism of the anti-tumor effect of T. spiralis infection. Our results showed a certain level of decreased progression of the tumor in HCC-T. spiralis group as indicated by increased rate of apoptosis and subsequently had a positive impact on the survival of rats.
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Schistosome Infection and Schistosome-Derived Products as Modulators for the Prevention and Alleviation of Immunological Disorders

Parasitic helminths, comprising the flatworms (tapeworms and flukes) and nematodes (roundworms), have plagued humans persistently over a considerable period of time. It is now known that the degree of exposure to these and other pathogens inversely correlates with the incidence of both T helper 1 (Th1)-mediated autoimmunity and Th2-mediated allergy. Accordingly, there has been recent increased interest in utilizing active helminth worm infections and helminth-derived products for the treatment of human autoimmune and inflammatory diseases and to alleviate disease severity. Indeed, there is an accumulating list of novel helminth derived molecules, including proteins, peptides, and microRNAs, that have been shown to exhibit therapeutic potential in a variety of disease models. Here we consider the blood-dwelling schistosome flukes, which have evolved subtle immune regulatory mechanisms that promote parasite survival but at the same time minimize host tissue immunopathology. We review and discuss the recent advances in using schistosome infection and schistosome-derived products as therapeutics to treat or mitigate human immune-related disorders, including allergic asthma, arthritis, colitis, diabetes, sepsis, cystitis, and cancer.

Schistosoma mansoni eggs induce Wnt/β-catenin signaling and activate the protooncogene c-Jun in human and hamster colon

Schistosomiasis (bilharzia) is a neglected tropical disease caused by parasitic flatworms of the genus Schistosoma, with considerable morbidity in parts of the Middle East, South America, Southeast Asia, in sub-Saharan Africa, and particularly also in Europe. The WHO describes an increasing global health burden with more than 290 million people threatened by the disease and a potential to spread into regions with temperate climates like Corsica, France. The aim of our study was to investigate the influence of S. mansoni infection on colorectal carcinogenic signaling pathways in vivo and in vitro. S. mansoni infection, soluble egg antigens (SEA) and the Interleukin-4-inducing principle from S. mansoni eggs induce Wnt/β-catenin signaling and the protooncogene c-Jun as well as downstream factor Cyclin D1 and markers for DNA-damage, such as Parp1 and γH2a.x in enterocytes. The presence of these characteristic hallmarks of colorectal carcinogenesis was confirmed in colon biopsies from S. mansoni-infected patients demonstrating the clinical relevance of our findings. For the first time it was shown that S. mansoni SEA may be involved in the induction of colorectal carcinoma-associated signaling pathways.

Murine hepatoma treatment with mature dendritic cells stimulated by Trichinella spiralis excretory/secretory products

Excretory/Secretory Products (ESPs) of the nematode Trichinella spiralis contain antitumor-active substances that inhibit tumor growth. Mature dendritic cells (DCs) play a critical role in the antitumor immunity of the organism. As pathogen-derived products, it ought to be discussed whether T. spiralis ESPs will reduce the antitumor effect of mature DCs from the host before it is applied to patients' tumors. Therefore, the aim of this work was to evaluate the immunological effect of DCs stimulated by T. spiralis ESPs in H22 tumor-bearing mice. H22 tumor model mice in this study were randomly divided into four groups according to the treatment: PBS control group, ESP group, DCs group, and DCs stimulated with T. spiralis ESP (ESP+DCs group). The antitumor effect was evaluated by tumor inhibition rate and cytokine detection using ELISA. The results showed significant inhibition in tumor growth in the ESP+DCs, DCs and ESP groups when compared with the PBS control group (p < 0.01, p < 0.01, and p < 0.05, respectively). However, no significant difference was observed on tumor inhibition rates between the ESP+DCs and DCs groups. The decrease in IL-4, IL-6, and IL-10, and the increase in IFN-γ between the DCs and ESP+DCs groups were also not significant. Therefore, DCs stimulated by ESP did not reduce the antitumor effect of mature DCs, which demonstrated that the T. spiralis ESP would not affect the antitumor effect of mature DCs by modulating the immune response of the host, and that ESPs are safe in antitumor immunology when applied in a tumor model mice.