Department of Genetic, Institute of Biological Sciences, Federal University of Goias – UFG, Goiânia, GO, Brazil. Cisplatin-based drugs are still the most widely anticancer drugs used in the world. The emergence of resistance to chemotherapeutic treatment has been shown to be a problem and a challenge in the cure of breast cancers. The ruthenium complexes have been objects of great attention due to their antimetastatic properties, low toxicity and various oxidation states under physiological conditions. In the present study, two ruthenium complexes, LGMC-68(DPPM) and LGMC–69(DPPE), were tested in MDA-MB-231 breast tumor cell line, using their respective IC50 values, 0.075µM (DPPM) and 0.21µM (DPPE), obtained by MTT assay. We used flow cytometry to evaluate the cell death mechanism of MDA-MB-231 cells, through the tests: Cell Cycle Analysis; Anexin V-FITC/Propidium Iodide Assay and JC-1 Assay. Cell cycle results demonstrated that MDA-MB-231 submitted to treatments showed a statistically significant G0/G1 phase arrest, with a percentage of 66.11%(DPPM) and 65.61%(DPPE), compared with 55.20% in negative control cells (p<0.001). These results were associated with a statistically significant decrease in the proportion of cells in S phase (22.9% and 20.36%, respectively), comparing with negative control (36.86%). Anexin V-FITC results demonstrated that MDA-MB-231 treated with 0.075µM DPPM for 48h presented significant amounts of late apoptotic cells (Annexin V+/PI+), specifically 23.39%, compared to the control (2.48%).The percentage of late apoptotic cells treated with 0.21µM DPPE was 17.5%. It was not observed significant amount of cells in early apoptotis (Annexin V+/PI-) or in necrosis in this test. JC-1 assay results showed that these ruthenium complexes induced significant loss of mitochondrial membrane potential in the MDA-MB-231. The percentage of cells with depolarized mitochondria increased from 10.2% (control) to 25.2% (0.075µM DPPM) and 35.3% (0.21µM DPPE). Thus, these complexes have been shown to be promising for triple negative breast cancer treatment and additional investigations on protein expression are required to confirm the mechanism of cell death. Breast Cancer, cell death mechanism, Ruthenium complexes.
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MECHANISMS OF CELL DEATH IN TRIPLE NEGATIVE BREAST CANCER TRIGGERED BY RUTHENIUM COMPLEXES
Vivianne S. V Sá, Aliny P. Lima, Wanessa P. Carvalho, Francielly M. S. Mello, Luciano R. Pereira, Alzir A. Batista, Elisângela P. Silveira- Lacerda
Department of Genetic, Institute of Biological Sciences, Federal University of Goias – UFG, Goiânia, GO, Brazil. Cisplatin-based drugs are still the most widely anticancer drugs used in the world. The emergence of resistance to chemotherapeutic treatment has been shown to be a problem and a challenge in the cure of breast cancers. The ruthenium complexes have been objects of great attention due to their antimetastatic properties, low toxicity and various oxidation states under physiological conditions. In the present study, two ruthenium complexes, LGMC-68(DPPM) and LGMC–69(DPPE), were tested in MDA-MB-231 breast tumor cell line, using their respective IC50 values, 0.075µM (DPPM) and 0.21µM (DPPE), obtained by MTT assay. We used flow cytometry to evaluate the cell death mechanism of MDA-MB-231 cells, through the tests: Cell Cycle Analysis; Anexin V-FITC/Propidium Iodide Assay and JC-1 Assay. Cell cycle results demonstrated that MDA-MB-231 submitted to treatments showed a statistically significant G0/G1 phase arrest, with a percentage of 66.11%(DPPM) and 65.61%(DPPE), compared with 55.20% in negative control cells (p<0.001). These results were associated with a statistically significant decrease in the proportion of cells in S phase (22.9% and 20.36%, respectively), comparing with negative control (36.86%). Anexin V-FITC results demonstrated that MDA-MB-231 treated with 0.075µM DPPM for 48h presented significant amounts of late apoptotic cells (Annexin V+/PI+), specifically 23.39%, compared to the control (2.48%).The percentage of late apoptotic cells treated with 0.21µM DPPE was 17.5%. It was not observed significant amount of cells in early apoptotis (Annexin V+/PI-) or in necrosis in this test. JC-1 assay results showed that these ruthenium complexes induced significant loss of mitochondrial membrane potential in the MDA-MB-231. The percentage of cells with depolarized mitochondria increased from 10.2% (control) to 25.2% (0.075µM DPPM) and 35.3% (0.21µM DPPE). Thus, these complexes have been shown to be promising for triple negative breast cancer treatment and additional investigations on protein expression are required to confirm the mechanism of cell death. Breast Cancer, cell death mechanism, Ruthenium complexes.