Effect of two hydatid cyst antigens on the growth of melanoma cancer in C57/black mice

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.

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.

In vitro anticancer activity of hydatid cyst fluid on colon cancer cell line (C26)

Background

Colon cancer is the third most common cancer and the fourth leading cause of death from cancer. Some parasites are introduced as an antineoplastic agents that can inhibit the progress of some cancers. The aim of this study was to investigate the effect of crude hydatid cyst fluid (HCF) on clone cancer cell line (C26).

Methods

HCF was isolated from hydatid cysts by syringe, and at the first, its toxicity was obtained by 2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Cell cycle analysis and apoptosis were measured by flow cytometer, and also the expression of Bcl-2 Associated X-protein (BAX) and B-cell lymphoma-2 (BCL2) genes was measured by quantitative reverse transcription PCR.

Results

The amount of apoptosis was increased in B antigen-treated cell lines in comparison with the control group. Also, the expression of BAX was increased in the treated group, while the BCL2 expression was decreased in comparison with the control one. Cell cycle analysis in the antigen-treated group compared to the other groups showed that the cells were more in the G0/G1 phase, as well as in the G2/M phase, and fewer cells were in the synthesis phase.

Conclusion

Our finding showed that HCF possibly contains active compounds and can limit the growth and development of C26 cell line by reducing or increasing the genes involved in apoptosis and finally the effect on the cell cycle.

Graphical Abstract

In vitro anti-gastrointestinal cancer activity of Toxocara canis-derived peptide: Analyzing the expression level of factors related to cell proliferation and tumor growth

Background: Recently, a hypothesis about the negative relationship between cancers and parasites has been proposed and investigated; some parasitic worms and their products can affect the cancer cell proliferation. Due to the potential anti-cancer effect of helminthic parasites, in the present study, the excretory–secretory protein of Toxocara canis (T. canis) parasite was used to evaluate the possible anti-cancer properties and their effect on gastrointestinal and liver cancer cell proliferation-related genes in laboratory conditions.

Methods and materials: The selected synthesized peptide fraction from the T. canis excretory–secretory Troponin protein peptide (ES TPP) was exposed at 32, 64, 128, and 256 μg/ml concentrations to three gastrointestinal cancer cell lines AGS, HT-29, and Caco 2, as well as HDF cells as normal cell lines. We used the MTT assay to evaluate cellular changes and cell viability (CV). Variations in gene (Bcl-2, APAF1, ZEB1, VEGF, cyclin-D1, and caspase-3) expression were analyzed by real-time RT-PCR.

Results: After 24 h of exposure to pept1ides and cell lines, a decrease in CV was observed at a concentration of 64 μg/ml and compared to the control group. Then, after 48 h, a significant decrease in the CV of Caco 2 cells was observed at a concentration of 32 μg/ml; in the other cancer cell lines, concentrations above 32 μg/ml were effective. The peptide was able to significantly alter the expression of the studied genes at a concentration of 100 μg/ml.

Conclusion: Although the studied peptide at high concentrations could have a statistically significant effect on cancer cells, it is still far from the standard drug and can be optimized and promising in future studies.

Parasites in surgically removed appendices as a neglected public health concern: a systematic review and meta-analysis

The role of various parasitic infections in the occurrence of appendicitis is illustrated through cases recorded all over the world. The purpose of the current study was to estimate the global prevalence of parasite infestation (other than E. vermicularis) in appendectomy specimens.In the setting of the PRISMA guidelines, multiple databases (Science Direct, Scopus, Web of Science, PubMed, and Google Scholar) were explored in articles published until 28 September 2020. Totally, 62 studies (106 datasets) with 77, 619 participants were included in the analysis.The pooled prevalence of parasites in appendectomy samples was as follows; 0.012% (95% CI; 0.004-0.025) for Ascaris lumbricoides, 0.004% (95% CI; 0.001-0.009) for Trichuris trichiura, 0.025% (95% CI; 0.007-0.052) for Schistosoma mansoni, 0.002% (95% CI; 0.001-0.005) for Taenia spp., 0.061% (95% CI; 0.020-0.122) for Entamoeba histolytica and 0.034% (95% CI; 0.018-0.056) for Giardia lamblia.Our results demonstrated that the risk of appendicitis may increase in the presence of helminth and protozoan infections. As such, the most cases of parasites in appendectomy specimens were reported in developing countries. Regular screening plans for diagnosis, treatment and prevention are needed for prevention of parasitic infection as well as parasitic associated appendicitis, especially in endemic regions of the world.

Echinococcus granulosus protoscoleces promotes proliferation and invasion of hepatocellular carcinoma cells

There may exist a connection between Echinococcus granulosus infection and cancer development. Here, it is aimed to investigate specific effects of E. granulosus protoscoleces (PSCs) on the proliferation and invasion capacities of hepatocellular carcinoma (HCC) cells in vitro and ex vitro. HepG2 cells were cultured with different quantities of E. granulosus PSCs in vitro. MTT analysis was used to evaluate effects of E. granulosus PSCs on the proliferation of HepG2 cells. Besides, scratch and transwell assays were respectively used for the detection of HepG2 cells migration and invasion capacities after co-culture with E. granulosus PSCs. Then, HepG2 cells were subcutaneously transplanted into nude mice with or without E. granulosus PSCs. From the 25th day of transplantation, the volume of subcutaneous lesions was measured every four days. At the 37th day, subcutaneous lesions were removed and their weight was evaluated. H&E staining was used for detecting basic pathological changes. HepG2 cells grew well without obvious morphological changes. Proliferation rate and migration capacity of HepG2 cells were higher in the co-culture group than the control group, which was closely associated with quantities of E. granulosus PSCs and co-culture time length. Moreover, HepG2 cells co-cultured with E. granulosus PSCs had stronger invasion ability than the control HepG2 cells. Importantly, there existed significant differences in the volume and weight of subcutaneous lesions after transplanting HepG2 cells with E. granulosus PSCs than the control group. HepG2 cells were also more pathologically heterogeneous in morphology after transplantation with E. granulosus PSCs. Thus, E. granulosus PSCs may promote proliferation and invasion of HCC cells.

Immunoregulatory Effects of Somatic Extract of Toxocara canis on Airway Inflammations in Murine Model

Background:

The immunomodulatory role of many parasites is well-documented. The current study designed to assess the immunoregulatory effects of the somatic extract (SE) of Toxocara canis on murine model of airway inflammations.

Methods:

The experiment was performed in department of parasitology of Tarbiat Mo-dares University, Tehran, Iran from November 2018 to May 2019. Totally 30 female BALB/c mice divided into one control group and two experimental groups (10 mice in each group). The ovalbumin (OVA) group was sensitized with OVA in alum, while the SE group was administered with SE and OVA in alum intraperitoneally. The control group was injected with PBS in alum. Then, SE and OVA groups were intranasally challenged with OVA for three consecutive days and the control group encountered with PBS at the same time. One day after the last challenge, real-time PCR and histopathology survey were conducted on isolated lung tissues.

Results:

The gene expression of IL-25, IL-33, TNF-α and TLR-4 in SE group was significantly lower than OVA group (P<0.05). The level of IL-10, TGF-β and IFN-γ were considerably higher than the OVA group (P<0.05). The inflammation was reduced in SE group, as the total cell number of bronchoalveolar lavage fluid was less than OVA group. Based on the histopathology findings the inflammation was decreased in SE group compared to the OVA group.

Conclusion:

Although, an inhibitory effect of SE of T. canis on airway inflammations was detected, there is still a long way ahead regarding the indication of the precise mechanisms.

Immunization with Hydatid Cyst Wall Antigens Can Inhibit Breast Cancer through Changes in Serum Levels of Th1/Th2 Cytokines

Background

Hydatid cysts are the larval stage of Echinococcus granulosus, which lead to humoral and cellular immune responses in hosts. Such immune responses play a key role in the inhibition of tumor growth and cancers. To test this hypothesis, it was attempted not only to examine the changes in serum level of some Th1 and Th2 cytokines but also to find relationships between the cytokines and cancer in 4T1 breast cancer-bearing mice immunized with hydatid cyst wall (HCW) antigens.

Methods

Six to eight-week-old Balb/c female mice were immunized with alum, PBS and HCW antigens, including crude extract of HCW (laminated layer) 28 and 27 kDa protein bands (upper and lower bands) and then challenged with 4T1 breast cancer cells. The amounts of IL2, TNF-α, IFN-γ (Th1 cytokines), and IL4 (Th2 cytokine) were estimated using ELISA. Correlations between these cytokines and cancer parameters (tumor growth, metastasis, and survival) were determined by Pearson's correlation coefficients.

Results

Overall, HCW antigens increased the amounts of IL2, TNF-α, IFN-γ, and IL4. Pearson's correlation coefficients indicated reverse relationships between changes in amounts of these cytokines and tumor growth/metastasis. However, except for IL-4, all cytokines had a direct relationship with mouse survival.

Conclusions

The results of this study indicated that the inhibition of breast tumor growth and metastasis and improvement of survival in 4T1 mice immunized with HCW antigens, especially laminated layer and 27 kDa protein band can occur through a rise in the levels of cytokines.

In vivo and in vitro studies using Clonorchis sinensis adult-derived total protein (CsTP) on cellular function and inflammatory effect in mouse and cell model

Clonorchis sinensis (C. sinensis) can induce a food-borne parasitic disease (clonorchiasis). Numerous studies have analyzed functional proteins, immunologic factors, pro-inflammatory cytokines, and cell signaling transduction that promote the development of clonorchiasis. In a previous study, it was shown that C. sinensis adult-derived total protein (CsTP) might be involved in the pathogenesis and development of liver fibrosis via bringing about Th2 immune response. In the present study, further investigation of CsTP on cellular function and inflammatory effect in vitro and in vivo has been elicited. CsTP induced inflammation and autophagy as evidenced by upregulation of TNF-α, IFN-γ, and autophagic markers LC3B and P62. Exposed to CsTP upregulated the antiapoptotic gene Bcl-2 expression, diminished the apoptosis induced by H₂O₂, but promoted the proliferation and migration of LX-2 cells in proper concentration range. Additionally, the protein levels of p-AKT and p-mTOR were repressed in response to CsTP, suggesting a correlation of blocking the activation of mTOR/AKT signaling pathway. These results revealed that CsTP might exacerbate hepatic pathological changes by regulating cell proliferation, apoptosis, autophagy, and inflammation in the liver and LX-2 cells. Some effects might be partially involved in the mTOR and AKT pathways.

Co-existence of hepatocellular carcinoma and cystic echinococcosis

PURPOSE

Co-existence of hepatocellular carcinoma (HCC) and cystic echinococcus (CE) is extremely rare. Echinococcus granulosus may exhibit a protective effect against cancer. Herein, this study aimed to evaluate the possible effects of echinococcal infection on HCC patients.

METHODS

Three thousand three hundred hepatic CE patients and 815 HCC patients were retrospectively reviewed between January 2010 and December 2018 in Xinjiang, China, and these patients were 1:5 matched according to their sex, age and tumor TMN stage, and only 13 patients coexisted both CE and HCC. Preoperative ultrasonography (US), computed tomography (CT), liver magnetic resonance imaging (MRI) and dot immune-gold filtration assay (DIGFA) were used for preoperative identification and intraoperative specimens from liver resections were pathologically examined for further confirmation. Survival time was analyzed through Cox proportional hazard model analysis.

RESULTS

The co-existing incidence rate of two diseases was 0.39%. For these concurrent cases, HCC was all at the advanced stage and CE lesions were inactive. Median survival time for HCC patients was 6 month (1-17). However, it was 8 month (3-90) for the co-existing cases and was much longer than the median survival time of HCC patients (P<0.05), which was closely associated with tumor size, location, TMN stage and hydatid size, location, classification. Four of the patients underwent surgical intervention and their median survival time was 17 month (3-68).

CONCLUSIONS

Echinococcus granulosus may elicit a protective effect against the development and progression of HCC, while more basic and clinical researches are needed.

Identifying the Most Effective Hydatid Cyst Fluid Fraction for Anticancer Vaccination of 4T1 Breast Tumor-Bearing Mice

Background:

The hydatid cyst fluid antigens have high homology with cancer cell antigens and also exhibit considerable immunogenicity. Therefore, their utilization for cancer immunization can cause an effective antitumor immune response. However, the main challenge is identifying the most effective antigens for this purpose.

Methods:

Hydatid cyst fluid fractions including the glycolipid fraction, glycoprotein fraction, 78 kDa fraction, and antigen B fraction were prepared. Then, the BALB/c mice were immunized against different antigens and, subsequently, 4T1 cells were subcutaneously implanted. The tumors' growth, metastasis, and tumor-bearing mice survival were assessed in different immunized groups. In addition, IL-2, IL-4, IFN-γ, and TNF-α serum levels were estimated to evaluate the immune system response.

Results:

BALB/c mice immunization against the complete hydatid cyst fluid antigens exhibited more significant inhibition of the tumors' growth and metastasis and increase of tumor-bearing mice survival in comparison with its derived fractions. However, the 78 kDa fraction exhibited the best results according to the same factors in comparison with all the prepared fractions.

Conclusions:

The 78 kDa fraction of the hydatid cyst fluid was the most effective fraction of hydatid cyst fluid for immunization against 4T1 breast tumors.

Effect of Hydatid Cyst Fluid Antigens on Induction of Apoptosis on Breast Cancer Cells

Background

Hydatid cyst is a zoonotic and parasitic disease with worldwide distribution. Anticancer effects of hydatid cyst have been shown in cell culture experiments and animal model investigations. The mechanism of anti-cancer effects of hydatid cyst fluid has not been clearly elucidated, and the induction of apoptosis may have a role in this regard. Hence, in this study, the effect of hydatid cyst fluid (HCF) on the induction of apoptosis on mouse breast cancer (4T1) cell line in cell culture medium has been investigated.

Materials and Methods

Echinococcus granulosus HCF antigens including Antigen B (AgB), glycolipid, glycoprotein, and 78 KDa fractions were prepared. Breast cancer cell line (4T1) was cultured in RPMI-1640 medium supplemented with 10% fetal bovine serum and appropriate antibiotics. Apoptosis was determined by flow cytometry using the annexin V-fluorescein isothiocyanate apoptosis kit.

Results

The 78 KDa and glycoprotein fractions induced more than 40% apoptosis. HCF and glycolipid antigens induced 39% and 34% apoptosis, respectively. However, less apoptosis observed after treatment with AgB fraction.

Conclusion

Hydatid cyst antigens especially the 78 KDa and glycoprotein fractions induced apoptosis on mouse breast cancer cells.

Anti-Toxoplasma gondii antibodies attach to mouse cancer cell lines but not normal mouse lymphocytes

Toxoplasma gondii (T. gondii) is prevalent intracellular parasite and a cause of worldwide infection in the human population. An inhibitory effect of this parasite on cancer growth has been demonstrated in cell culture and animal models. To determine whether the anticancer activities of T. gondii are associated with host immune response, in the current study the reactivity of anti-T. gondii antiserum with the surface of cancer cell lines was investigated. Anti-T. gondii antibodies were raised in rabbit and the reaction of this antiserum in comparison with other anti-parasite antisera (anti-T. vaginalis, anti-hydatid cyst fluid, anti-protoscolices antigens) with mouse melanoma or breast cancer cells lines was investigated using flow cytometry. Anti-T. gondii antiserum reacted markedly with the surface of mouse melanoma and breast cancer cells, and less so with the normal mouse spleen lymphocytes. Meanwhile, the other anti-parasite antisera did not react strongly with the surface of cancer cells compared with normal mouse spleen lymphocytes. In summary, it has been demonstrated herein that anti-T. gondii antiserum may selectively react with the surface of mouse cancer cells but not with normal mouse spleen lymphocytes. Therefore, further study on anti-Toxoplasma antibodies may be useful for directing the application of selective drug delivery in cancer treatment.

Modulation of human melanoma cell proliferation and apoptosis by hydatid cyst fluid of Echinococcus granulosus

Objective

The objective of this paper was to assess the effects of hydatid cyst fluid (HCF) of Echinococcus granulosus on melanoma A375 cell proliferation and apoptosis.

Methods

A375 cells were classified into five groups by in vitro culture: normal group, control group, 10% HCF group, 20% HCF group and 30% HCF group. Trypan blue staining method was employed to detect the toxicity of HCF. Effects of different concentrations of HCF on melanoma A375 cell proliferation at different time points were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Flow cytometry and propidium iodide (PI) staining were used to detect cell cycle, and Annexin-V/PI double staining method was used to determine A375 cell apoptotic rate. Western blotting was applied to detect the expression of phosphorylated extracellular regulated protein kinases, proliferating cell nuclear antigen (PCNA), cell-cycle-related proteins (cyclin A, cyclin B1, cyclin D1 and cyclin E) and apoptosis-related proteins (Bcl-2, Bax and caspase-3).

Results

HCF with a high concentration was considered as atoxic to A375 cells. HCF promoted A375 cell proliferation, and the effects got stronger with an increase in concentrations but was retarded after reaching a certain range of concentrations. HCF increased phosphorylation level and expression of extracellular regulated protein kinase, as well as PCNA expression. HCF also promoted the transferring progression of A375 cells from the G0/G1 phase to the S phase to increase the cell number in S phase and increased the expression of cyclin A, cyclin D1 and cyclin E. HCF increased the expression of procaspase-3 (the precursor of apoptosis-related protein caspase-3) and antiapoptotic protein-Bcl-2, and decreased the expression of proapoptotic factor Bax, thereby inhibiting cell apoptosis.

Conclusion

As a result, this study confirmed that HCF promotes proliferation and inhibits apoptosis of melanoma A375 cells.