Suppressed CD31 Expression in Sarcoma-180 Tumors after Injection with Toxoplasma gondii Lysate Antigen in BALB/c Mice

Abstract

The anti-tumorigenic effects of Toxoplasma gondii (RH) antigens were studied in a murine sarcoma-180 tumor model. To determine the anti-tumor effects, the reduction in tumor size and expression of CD31 (an angiogenesis marker in the tumor tissue) were examined after injection of BALB/c mice with T. gondii lysate antigen (TLA) or formalin-fixed, proliferation-inhibited, T. gondii tachyzoites. Tumors were successfully produced by an intradermal injection of sarcoma-180 cells with plain Matrigel in the mid-backs of mice. After injection with TLA or formalin-fixed T. gondii tachyzoites, the increase in tumor size and weight nearly stopped while tumor growth continued in control mice that were injected with PBS. CD31 expression in TLA-treated or formalin-fixed T. gondii-injected mice was lower than the control mice. Accordingly, the present study shows that the treatment of mice with formalin-fixed T. gondii or TLA in the murine sarcoma-180 tumor model results in a decrease of both tumor size and CD31 expression.

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

“…Toxoplasma gondii (T. gondii) is a protozoan parasite that infects approximately 1/3 of the human population worldwide (1). Anticancer activities of this parasite have been demonstrated in previous studies (2)(3)(4). Notably, it has been observed that non-replicating T. gondii reverses tumor associated immunosuppression (5).…”

“…Notably, it has been observed that non-replicating T. gondii reverses tumor associated immunosuppression (5). Antitumor effects of T. gondii antigens in a murine sarcoma 180 tumor model have also been demonstrated (4). In another study, Balb/c inbred mice were injected with T. gondii antigens and then challenged with WEHI-164 fibrosarcoma cells, and significant inhibition of tumor growth was observed (6).…”

Targeting tumors with nonreplicating Toxoplasma gondii uracil auxotroph vaccines

“…For example, Toxoplasma was used more than 5 decades ago to demonstrate anti-tumor effects [26]. Protein extracts from killed Toxoplasma demonstrated measurable effects in slowing the development of various tumors such as fibrosarcoma [27], lung [28], melanoma [29], sarcoma [30, 31], and chemically-induced tumors [32]. Other studies have used live Toxoplasma to demonstrate measurable effects in slowing the development of bladder [33], brain [34], leukemia [35], Lewis lung [36], melanoma [37, 38], and sarcoma [35] tumors in mice.…”

Prominent IL-12 Production and Tumor Reduction in Athymic Nude Mice after Toxoplasma gondii Lysate Antigen Treatment

“…Recently, T. gondii infection has been highlighted to be helpful in some diseases. In this regard, our previous study examined the favorable effects of T. gondii infection and T. gondii lysate antigen (TLA) on neurodegenerative diseases and tumor induction [ 3 , 4 ]. In particular, the anti-tumorigenic effect of the TLA injection was due to a decrease in CD31 for anti-angiogenesis playing a potential role in reducing the tumor mass [ 3 ].…”

“…In this regard, our previous study examined the favorable effects of T. gondii infection and T. gondii lysate antigen (TLA) on neurodegenerative diseases and tumor induction [ 3 , 4 ]. In particular, the anti-tumorigenic effect of the TLA injection was due to a decrease in CD31 for anti-angiogenesis playing a potential role in reducing the tumor mass [ 3 ]. TLA treatment also delayed the tumor formation in the early stage of tumor growth in 20-methylcholanthrene-induced tumors [ 5 ].…”