Melastoma malabathricum Ethyl Acetate Fraction Induces Secondary Necrosis in Human Breast and Lung Cancer Cell Lines

Melastoma malabathricum (MM) is a traditional plant used in the Borneo region. The cytotoxic effects of methanol extracts from MM leaves have been reported in a number of human cancer cell lines. However, the mode of cell death by MM has not been investigated.

We investigated the cytotoxic effects of MM in both human breast and lung cancer cell lines, MCF-7 and A549, respectively, and defined the mode of cell death.

Cell viability was measured using the 3-(4-, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Annexin-V/propidium iodide (PI) and terminal deoxynucleotidyl transferase dUTP nick-end labeling (TUNEL) staining was done to determine the mode of cell death.

The MTT assay revealed that MM extract had an IC50 of >400 μg/ml on both cell lines at 24 h posttreatment. Flow cytometric and fluorescence microscopy analysis of Annexin-V/PI stained MM-treated cells revealed that the majority of the cells underwent secondary necrosis/late apoptosis. TUNEL assay showed that little to no DNA nicks were present in MM-treated cells, suggesting that cells have undergone secondary necrosis, not late apoptosis, at that time point.

MCF-7 and A549 cells undergoes secondary necrosis 24 h post-treatment with MM extract. MM leaf extract could be a potential source for a novel anti-tumor agent for cancer therapy.

Melastoma malabathricum (MM) extract was toxic on human breast and lung cancer cell linesMajority of MM-treated cells died by either secondary necrosis or late apoptosis at 24 h post-treatmentTerminal deoxynucleotidyl transferase dUTP nick-end labeling assay confirmed that MM-treated cells underwent secondary necrosis, not late apoptosis. Abbreviations used: DMSO: Dimethyl sulfoxide; MM: Melastoma malabathricum; MTT: 3-(4-, 5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide; PI: Propidium iodide; TUNEL: Terminal deoxynucleotidyl transferase dUTP nick-end labeling.