Targeting of antitumor ımmune responses with live-attenuated Leishmania strains in breast cancer model

How tapeworms interact with cancers: a mini-review

Cancer is one of the leading causes of death, with an estimated 19.3 million new cases and 10 million deaths worldwide in 2020 alone. Approximately 2.2 million cancer cases are attributed to infectious diseases, according to the World Health Organization (WHO). Despite the apparent involvement of some parasitic helminths (especially trematodes) in cancer induction, there are also records of the potential suppressive effects of helminth infections on cancer. Tapeworms such as Echinococcus granulosus, Taenia crassiceps, and more seem to have the potential to suppress malignant cell development, although in a few cases the evidence might be contradictory. Our review aims to summarize known epidemiological data on the cancer-helminth co-occurrence in the human population and the interactions of tapeworms with cancers, i.e., proven or hypothetical effects of tapeworms and their products on cancer cells in vivo (i.e., in experimental animals) or in vitro. The prospect of bioactive tapeworm molecules helping reduce the growth and metastasis of cancer is within the realm of future possibility, although extensive research is yet required due to certain concerns.

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.

Anti-Tumor Effect of Parasitic Protozoans

The immune system may aberrantly silence when against “altered self”, which consequently may develop into malignancies. With the development of tumor immunology and molecular biology, the deepened understanding of the relationship between parasites and tumors shifts the attitude towards parasitic pathogens from elimination to utilization. In recent years, the antitumor impact implemented by protozoan parasites and the derived products has been confirmed. The immune system is activated and enhanced by some protozoan parasites, thereby inhibiting tumor growth, angiogenesis, and metastasis in many animal models. In this work, we reviewed the available information on the antitumor effect of parasitic infection or induced by parasitic antigen, as well as the involved immune mechanisms that modulate cancer progression. Despite the fact that clinical trials of the protozoan parasites against tumors are limited and the specific mechanisms of the effect on tumors are not totally clear, the use of genetically modified protozoan parasites and derived molecules combined with chemotherapy could be an important element for promoting antitumor treatment in the future.

In Silico Characterization of Calcineurin from Pathogenic Obligate Intracellular Trypanosomatids: Potential New Biological Roles

Calcineurin (CaN) is present in all eukaryotic cells, including intracellular trypanosomatid parasites such as Trypanosoma cruzi (Tc) and Leishmania spp. (Lspp). In this study, we performed an in silico analysis of the CaN subunits, comparing them with the human (Hs) and looking their structure, post-translational mechanisms, subcellular distribution, interactors, and secretion potential. The differences in the structure of the domains suggest the existence of regulatory mechanisms and differential activity between these protozoa. Regulatory subunits are partially conserved, showing differences in their Ca²⁺-binding domains and myristoylation potential compared with human CaN. The subcellular distribution reveals that the catalytic subunits TcCaNA1, TcCaNA2, LsppCaNA1, LsppCaNA1_var, and LsppCaNA2 associate preferentially with the plasma membrane compared with the cytoplasmic location of HsCaNAα. For regulatory subunits, HsCaNB-1 and LsppCaNB associate preferentially with the nucleus and cytoplasm, and TcCaNB with chloroplast and cytoplasm. Calpain cleavage sites on CaNA suggest differential processing. CaNA and CaNB of these trypanosomatids have the potential to be secreted and could play a role in remote communication. Therefore, this background can be used to develop new drugs for protozoan pathogens that cause neglected disease.

Potential therapeutic targets shared between leishmaniasis and cancer

The association of leishmaniasis and malignancies in human and animal models has been highlighted in recent years. The misdiagnosis of coexistence of leishmaniasis and cancer and the use of common drugs in the treatment of such diseases prompt us to further survey the molecular biology of Leishmania parasites and cancer cells. The information regarding common expressed proteins, as possible therapeutic targets, in Leishmania parasites and cancer cells is scarce. Therefore, the current study reviews proteins, and investigates the regulation and functions of several key proteins in Leishmania parasites and cancer cells. The up- and down-regulations of such proteins were mostly related to survival, development, pathogenicity, metabolic pathways and vital signalling in Leishmania parasites and cancer cells. The presence of common expressed proteins in Leishmania parasites and cancer cells reveals valuable information regarding the possible shared mechanisms of pathogenicity and opportunities for therapeutic targeting in leishmaniasis and cancers in the future.