This work investigated the anti-amoebic activity of two samarium (Sm) complexes, the acyclic complex [bis(picrato)(pentaethylene glycol)samarium(III)] picrate-referred to as [Sm(Pic)2(EO5)](Pic)-and the cyclic complex [bis(picrato)(18-crown-6)samarium(III)] picrate-referred to as [Sm(Pic)2(18C6)](Pic). Both Sm complexes caused morphological transformation of the protozoa Acanthamoeba from its native trophozoite form carrying a spine-like structure called acanthopodia, to round-shaped cells with loss of the acanthopodia structure, a trademark response to environmental stress. Further investigation, however, revealed that the two forms of the Sm complexes exerted unique cytotoxicity characteristics. Firstly, the IC50 of the acyclic complex (0.7 μg/mL) was ~ 10-fold lower than IC50 of the cyclic Sm complex (6.5 μg/mL). Secondly, treatment of the Acanthamoeba with the acyclic complex caused apoptosis of the treated cells, while the treatment with the cyclic complex caused necrosis evident by the leakage of the cell membrane. Both treatments induced DNA damage in Acanthamoeba. Finally, a molecular docking simulation revealed the potential capability of the acyclic complex to form hydrogen bonds with profilin-a membrane protein present in eukaryotes, including Acanthamoeba, that plays important roles in the formation and degradation of actin cytoskeleton. Not found for the cyclic complex, such potential interactions could be the underlying reason, at least in part, for the much higher cytotoxicity of the acyclic complex and also possibly, for the observed differences in the cytotoxicity traits. Nonetheless, with IC50 values of
Metastasising ability connotes one of the most important life-threatening properties of malignant neoplasms. Recent studies indicate that CD44 proteins, multifunctional cell adhesion molecules which contribute to "homing" of lymphocytes to lymph nodes as well as cell-cell and cell-matrix interactions, are potential markers of tumour progression. However, whether CD44 expression by human tumours contribute to increased metastatic risk remains controversial. In an attempt to clarify its role in breast cancer, we have investigated the correlation between CD44 expression by breast carcinoma and the presence of axillary lymph node metastases. CD44 expression was detected using a standard immunoperoxidase method on formalin-fixed, paraffin-embedded, primary infiltrating ductal breast carcinoma tissues taken from 60 female patients who underwent mastectomy with axillary node clearance. Tumours were graded according to the modified Bloom and Richardson criteria. 62% of patients had histologically-proven lymph node metastasis. 40% of primary cancers exhibited cytoplasmic membrane immunopositivity for CD44. 46% of primary tumours which have metastasied to axillary lymph nodes were CD44 positive whereas 30% of tumours which have not metastasised expressed CD44. CD44 positivity was expressed by 20% of grade 1, 31% grade 2 and 58% grade 3 tumours. Our results suggest that CD44 may have a role in the progression of breast cancer and emphasise the need to investigate its interaction with other mechanisms of cancer advancement.