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Jacaric acid inhibits the growth of murine macrophage-like leukemia PU5-1.8 cells by inducing cell cycle arrest and apoptosis.

Liu WN, Leung KN - Cancer Cell Int. (2015)

Bottom Line: Previous researches have demonstrated that CLN can inhibit the growth of a wide variety of cancer cells, whereas the modulatory effect of CLN on various myeloid leukemia cells remains unclear.This study aims at demonstrating the in vitro anti-tumor effect and action mechanisms of jacaric acid, a CLN isomer which is present in jacaranda seed oil, on the murine macrophage-like leukemia PU5-1.8 cells.Flow cytometric analysis revealed the induction of G0/G1 cell cycle arrest, accompanied by a decrease in CDK2 and cyclin E proteins.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, HKSAR, China.

ABSTRACT

Background: Conjugated linolenic acids (CLN) refer to the positional and geometric isomers of octadecatrienoic acids with three conjugated double bonds (C18:3). Previous researches have demonstrated that CLN can inhibit the growth of a wide variety of cancer cells, whereas the modulatory effect of CLN on various myeloid leukemia cells remains unclear. This study aims at demonstrating the in vitro anti-tumor effect and action mechanisms of jacaric acid, a CLN isomer which is present in jacaranda seed oil, on the murine macrophage-like leukemia PU5-1.8 cells.

Methods and results: It was found that jacaric acid inhibited the proliferation of PU5-1.8 cells in a time- and concentration-dependent manner, as determined by the MTT reduction assay and by using CyQUANT(®) NF Cell Proliferation Assay Kit, while it exerted minimal cytotoxicity on normal murine cells. Besides, the reactive oxygen species production in jacaric acid-treated PU5-1.8 cells was elevated in a concentration-dependent mannar. Flow cytometric analysis revealed the induction of G0/G1 cell cycle arrest, accompanied by a decrease in CDK2 and cyclin E proteins. Jacaric acid also triggered apoptosis as reflected by induction of DNA fragmentation, phosphatidylserine externalization, mitochondrial membrane depolarization, up-regulation of pro-apoptotic Bax protein and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins.

Conclusions: Our results demonstrated the growth-inhibitory effect of jacaric acid on PU5-1.8 cells through inducing cell cycle arrest and apoptosis, while exhibiting minimal cytotoxicity to normal murine cells. Therefore, jacaric acid is a potential candidate for the treatment of some forms of myeloid leukemia with minimal toxicity and fewer side effects.

No MeSH data available.


Related in: MedlinePlus

Modulation of cell cycle profile and cell cycle-regulatory proteins in jacaric acid-treated PU5-1.8 cells. a PU5-1.8 cells were incubated with different concentrations of jacaric acid at 37 °C for 72 h. Cells treated with ethanol acted as the control. The DNA content was analyzed by PI staining and flow cytometry. Cell cycle distribution of the samples was calculated by Modfit LT 3.0 programme. The results were expressed as mean ± SE. *p < 0.05. b PU5-1.8 cells were incubated with 4 μM jacaric acid (Lane 2) and 8 μM jacaric acid (Lane 3) at 37 °C for 72 h. Cells treated with ethanol (Lane 1) acted as the control. Protein expression levels of CDK2, cyclin E, p21, p27 and pp53 were assayed by Western blotting with β-actin protein as an internal control. c–g The relative protein expression levels of CDK2, cyclin E, p21, p27 and pp53 compared to β-actin were quantified. Results represent mean ± SE. *p < 0.05; ***p < 0.001
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Fig5: Modulation of cell cycle profile and cell cycle-regulatory proteins in jacaric acid-treated PU5-1.8 cells. a PU5-1.8 cells were incubated with different concentrations of jacaric acid at 37 °C for 72 h. Cells treated with ethanol acted as the control. The DNA content was analyzed by PI staining and flow cytometry. Cell cycle distribution of the samples was calculated by Modfit LT 3.0 programme. The results were expressed as mean ± SE. *p < 0.05. b PU5-1.8 cells were incubated with 4 μM jacaric acid (Lane 2) and 8 μM jacaric acid (Lane 3) at 37 °C for 72 h. Cells treated with ethanol (Lane 1) acted as the control. Protein expression levels of CDK2, cyclin E, p21, p27 and pp53 were assayed by Western blotting with β-actin protein as an internal control. c–g The relative protein expression levels of CDK2, cyclin E, p21, p27 and pp53 compared to β-actin were quantified. Results represent mean ± SE. *p < 0.05; ***p < 0.001

Mentions: To determine the possible mechanisms of the anti-proliferative effect of jacaric acid on PU5-1.8 cells, cells were stained by propidium iodide (PI) after incubation with jacaric acid for 72 h, and the cell cycle profile was analyzed by flow cytometry. As shown in Fig. 5a, jacaric acid triggered cell cycle arrest at the G0/G1 phase, and accompanied by a decrease in the percentage of cells at the S phase. To further elucidate the underlying mechanisms, Western blotting was performed to examine the protein expression levels of cyclin-dependent kinase (CDK) 2, cyclin E, p21, p27 and pp53 (Fig. 5b), which are known to be involved in the transition of cell cycle from G0/G1 to S phase [18, 19]. Our results show that the protein expression levels of CDK2 and cyclin E decreased in jacaric acid-treated PU5-1.8 cells, whereas an elevation in the expression levels of the p21, p27 and pp53 proteins was observed (Fig. 5c–g). Collectively, the results indicate that jacaric acid treatment of PU5-1.8 cells could lead to the cell cycle arrest at the G0/G1 phase, and modulated the expression of certain cell cycle-regulatory proteins such as CDK2, cyclin E, p21, p27 and pp53.Fig. 5


Jacaric acid inhibits the growth of murine macrophage-like leukemia PU5-1.8 cells by inducing cell cycle arrest and apoptosis.

Liu WN, Leung KN - Cancer Cell Int. (2015)

Modulation of cell cycle profile and cell cycle-regulatory proteins in jacaric acid-treated PU5-1.8 cells. a PU5-1.8 cells were incubated with different concentrations of jacaric acid at 37 °C for 72 h. Cells treated with ethanol acted as the control. The DNA content was analyzed by PI staining and flow cytometry. Cell cycle distribution of the samples was calculated by Modfit LT 3.0 programme. The results were expressed as mean ± SE. *p < 0.05. b PU5-1.8 cells were incubated with 4 μM jacaric acid (Lane 2) and 8 μM jacaric acid (Lane 3) at 37 °C for 72 h. Cells treated with ethanol (Lane 1) acted as the control. Protein expression levels of CDK2, cyclin E, p21, p27 and pp53 were assayed by Western blotting with β-actin protein as an internal control. c–g The relative protein expression levels of CDK2, cyclin E, p21, p27 and pp53 compared to β-actin were quantified. Results represent mean ± SE. *p < 0.05; ***p < 0.001
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Fig5: Modulation of cell cycle profile and cell cycle-regulatory proteins in jacaric acid-treated PU5-1.8 cells. a PU5-1.8 cells were incubated with different concentrations of jacaric acid at 37 °C for 72 h. Cells treated with ethanol acted as the control. The DNA content was analyzed by PI staining and flow cytometry. Cell cycle distribution of the samples was calculated by Modfit LT 3.0 programme. The results were expressed as mean ± SE. *p < 0.05. b PU5-1.8 cells were incubated with 4 μM jacaric acid (Lane 2) and 8 μM jacaric acid (Lane 3) at 37 °C for 72 h. Cells treated with ethanol (Lane 1) acted as the control. Protein expression levels of CDK2, cyclin E, p21, p27 and pp53 were assayed by Western blotting with β-actin protein as an internal control. c–g The relative protein expression levels of CDK2, cyclin E, p21, p27 and pp53 compared to β-actin were quantified. Results represent mean ± SE. *p < 0.05; ***p < 0.001
Mentions: To determine the possible mechanisms of the anti-proliferative effect of jacaric acid on PU5-1.8 cells, cells were stained by propidium iodide (PI) after incubation with jacaric acid for 72 h, and the cell cycle profile was analyzed by flow cytometry. As shown in Fig. 5a, jacaric acid triggered cell cycle arrest at the G0/G1 phase, and accompanied by a decrease in the percentage of cells at the S phase. To further elucidate the underlying mechanisms, Western blotting was performed to examine the protein expression levels of cyclin-dependent kinase (CDK) 2, cyclin E, p21, p27 and pp53 (Fig. 5b), which are known to be involved in the transition of cell cycle from G0/G1 to S phase [18, 19]. Our results show that the protein expression levels of CDK2 and cyclin E decreased in jacaric acid-treated PU5-1.8 cells, whereas an elevation in the expression levels of the p21, p27 and pp53 proteins was observed (Fig. 5c–g). Collectively, the results indicate that jacaric acid treatment of PU5-1.8 cells could lead to the cell cycle arrest at the G0/G1 phase, and modulated the expression of certain cell cycle-regulatory proteins such as CDK2, cyclin E, p21, p27 and pp53.Fig. 5

Bottom Line: Previous researches have demonstrated that CLN can inhibit the growth of a wide variety of cancer cells, whereas the modulatory effect of CLN on various myeloid leukemia cells remains unclear.This study aims at demonstrating the in vitro anti-tumor effect and action mechanisms of jacaric acid, a CLN isomer which is present in jacaranda seed oil, on the murine macrophage-like leukemia PU5-1.8 cells.Flow cytometric analysis revealed the induction of G0/G1 cell cycle arrest, accompanied by a decrease in CDK2 and cyclin E proteins.

View Article: PubMed Central - PubMed

Affiliation: Biochemistry Programme, School of Life Sciences, The Chinese University of Hong Kong, Shatin, HKSAR, China.

ABSTRACT

Background: Conjugated linolenic acids (CLN) refer to the positional and geometric isomers of octadecatrienoic acids with three conjugated double bonds (C18:3). Previous researches have demonstrated that CLN can inhibit the growth of a wide variety of cancer cells, whereas the modulatory effect of CLN on various myeloid leukemia cells remains unclear. This study aims at demonstrating the in vitro anti-tumor effect and action mechanisms of jacaric acid, a CLN isomer which is present in jacaranda seed oil, on the murine macrophage-like leukemia PU5-1.8 cells.

Methods and results: It was found that jacaric acid inhibited the proliferation of PU5-1.8 cells in a time- and concentration-dependent manner, as determined by the MTT reduction assay and by using CyQUANT(®) NF Cell Proliferation Assay Kit, while it exerted minimal cytotoxicity on normal murine cells. Besides, the reactive oxygen species production in jacaric acid-treated PU5-1.8 cells was elevated in a concentration-dependent mannar. Flow cytometric analysis revealed the induction of G0/G1 cell cycle arrest, accompanied by a decrease in CDK2 and cyclin E proteins. Jacaric acid also triggered apoptosis as reflected by induction of DNA fragmentation, phosphatidylserine externalization, mitochondrial membrane depolarization, up-regulation of pro-apoptotic Bax protein and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins.

Conclusions: Our results demonstrated the growth-inhibitory effect of jacaric acid on PU5-1.8 cells through inducing cell cycle arrest and apoptosis, while exhibiting minimal cytotoxicity to normal murine cells. Therefore, jacaric acid is a potential candidate for the treatment of some forms of myeloid leukemia with minimal toxicity and fewer side effects.

No MeSH data available.


Related in: MedlinePlus