Characterization and Evaluation of the Anti-proliferative Activity and Hypersensitivity of L-Asparaginase from Trichosporon asahii Isolate ChL11 and Candida palmioleophila Isolate JK12

Background: L-Asparaginase is a crucial enzyme to treat Acute Lymphoblastic Leukemia (ALL), as it depletes L-asparagine, an essential amino acid for cancer cell survival. However, its clinical use is often restricted due to hypersensitivity reactions. This study examined the anti-proliferative effects and hypersensitivity of fungal L-aspara-ginases (L-ASNases) from Trichosporon asahii isolate ChL11 (TaIChL11 L-ASNase) and Candida palmioleophila isolate JK12 (CpIJK12 L-ASNase). Methods: The enzymes were produced and purified through ammonium sulfate precipitation, dialysis, and Sephadex G-100 chromatography, and tested on leukemia cells and BALB/c female mice to assess immune responses. Results: TaIChL11 L-ASNase had a molecular weight of 40 kDa, Michaelis constant (KM) of 1.66×10⁻² mM, and Vmax of 37.23 mM/min, while CpIJK12 L-ASNase had a molecular weight of 135 kDa, KM of 2.3×10⁻² mM, and Vmax of 14.03 mM/min. Both enzymes exhibited significant anti-proliferative effects against CCRF-CEM cancer cells, with half-maximal inhibitory concentration (IC50) values of 2.74 U/ml for TaIChL11 L-ASNase and 3.30 U/ml for CpIJK12 L-ASNase after 48 hr, improving further after 72 hr. They also showed low cytotoxicity toward normal Vero E6 cells. in vivo studies demonstrated that TaIChL11 ASNase-treated mice had significantly lower Immunoglobulin (Ig) G levels than those treated with commercial L-ASNase from Erwinia chrysanthemi (Owenism) (p<0.005), with no detectable IgE response. Conclusion: These findings indicate that fungal L-ASNases, particularly TaIChL11 ASNase, with lower L-glutaminase activity and a favorable safety profile, could be promising alternatives to bacterial L-ASNases, potentially enhancing ALL treatment with fewer side effects.