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

A potential cure for tumor-associated immunosuppression by Toxoplasma gondii

BACKGROUND

Recently, immunotherapy has become very hopeful for cancer therapy. Cancer treatment through immunotherapy has excellent specificity and less toxicity than conventional chemoradiotherapy. Pathogens have been used in cancer immunotherapy for a long time. The current study aims to evaluate the possibility of Toxoplasma gondii (T. gondii) as a probable treatment for cancers such as melanoma, breast, ovarian, lung, and pancreatic cancer.

RECENT FINDINGS

Nonreplicating type I uracil auxotrophic mutants of T. gondii can stimulate immune responses against tumors by reverse immunosuppression at the cellular level. T. gondii can be utilized to research T helper 1 (Th1) cell immunity in intracellular infections. Avirulent T. gondii uracil auxotroph vaccine can change the tumor's immunosuppression and improve the production of type 1 helper cell cytokines, i.e., Interferon-gamma (IFN-γ) and Interleukin-12 (IL-12) and activate tumor-related Cluster of Differentiation 8 (CD8+) T cells to identify and destroy cancer cells. The T. gondii profilin protein, along with T. gondii secreted proteins, have been found to exhibit promising properties in the treatment of various cancers. These proteins are being studied for their potential to inhibit tumor growth and enhance the effectiveness of cancer therapies. Their unique mechanisms of action make them valuable candidates for targeted interventions in ovarian cancer, breast cancer, pancreatic cancer, melanoma, and lung cancer treatments.

CONCLUSION

In summary, the study underscores the significant potential of harnessing T. gondii, including its diverse array of proteins and antigens, particularly in its avirulent form, as a groundbreaking approach in cancer immunotherapy.

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.