Iso-suillin from the mushroom Suillus flavus induces cell cycle arrest and apoptosis in K562 cell line

- Iso-suillin, was isolated from the petroleum ether extracts of Suillus flavus.
- The IC50 values of Iso-suillin on K562 cells lower than Cisplatin.
- Iso-suillin could induce K562 cell apoptosis through the mitochondrial pathway.
- Iso-suillin could induce K562 cell apoptosis through the death receptor pathway.
- Iso-suillin might serve as a candidate for anti-leukemia drug.

Iso-suillin, an isomer of suillin that belongs to the prenylphenol class of fungal derivatives, was isolated from petroleum ether extracts of Suillus flavus. The IC50 value of iso-suillin in K562 cells was 0.87 μM, which was lower than the positive control cisplatin (19.33 μM). Iso-suillin-treated K562 cells exhibited an increased rate of apoptosis, mitochondrial membrane potential (MMP) depolarization, and G0/G1 arrest. Western blot analysis revealed that these cells displayed significantly upregulated expression of several apoptosis-related proteins, including cytochrome c, caspase 9, FADD (Fas-associating protein with a novel death domain), caspase 8, caspase 3, and Bax. Moreover, the expression of two anti-apoptosis proteins, NF-κB and Bcl-2, was downregulated. Inhibitors of caspase 9 and caspase 8 protected the K562 cells from apoptosis. Taken together, our results suggest that iso-suillin induces K562 apoptosis through the mitochondrial and death receptor pathways and that iso-suillin may represent a candidate anti-leukemia treatment.

Iso-suillin was isolated from the petroleum ether extracts of Suillus flavus. Iso-suillin-treated K562 cells showed an increased apoptosis rate. Western blot analysis revealed that, in these cells, the expression of the proteins related to apoptosis including cytochrome c, Caspase 9, FADD, Caspase 8 ,Caspase 3 and Bax, were obviously up-regulated. Moreover, the expression of NF-κB and Bcl-2 was down-regulated. Our results suggest that Iso-suillin could induce K562 cell apoptosis through the mitochondrial pathway and the death receptor pathway and might serve as a candidate for anti-leukemia drug.