A Preliminary Study On Anti-cancer Small Molecule Drugs Of The Sesquiterpene Lactone Analogue

Chemotherapy is used most common to prescribe drugs to cure diseases or kill cancer in clinic,but high toxicity and drug resistance are the problems that frequently encounter.It is frequently that the drugs come from natural products have the potency of high efficiency and low toxicity. This project is to investigate the anti-tumor activity of the natural product parthenolide(PTL) and its analogs.For study on the inhibition effect of cancer cell proliferation by PTL analogs, MTT assay was applied to detect the effect of inhibition on HL-60, HL-60/ADR and KG la up to 72h.The apoptosis rate of patient stem cells was examined by flow cytometry. The result showed that some analogs have acceptable cytotocity on HL-60, HL-60/ADR, KGla, some analogs have better inhibition effect on HL-60 than HL-60/ADR, or without cytotocity. One of the PTL analogs-micheliolide (MCL) can selectively target patient stem cells.Study on the apoptosis of leukemia K562/ADR cell with multidrug resistance induced by parthenolide was carried out by MTT assay to detect the effect of inhibition on K562, K562/ADR for 72h. The apoptosis rate and reactive oxygen species (ROS) level of cells were examined by flow cytometry. The expression of proteins Bcl-2, Bax, caspase-3 and caspase-9 were measured by Western blot. PTL was shown to inhibit the growth and induce apoptosis of K562/ADR in a dose-dependant manner; but had no significant difference with the inhibition rate and the apoptosis rate on K562 cell. Increase of ROS levels were shown in K562 and K562/ADR cells after treatment of 10μM PTL for 1 h. The expression of Bcl-2/Bax, pro-caspase-3 and pro-caspase-9 were decreased by 10 A549 and CACO-2 PTL for 24 h. ROS increase apoptosis, but the cell apoptosis of K562/ADR could be inhibited by the antioxidant N-acetyl-L-cysteine (NAC) pretreatment. PTL induced apoptosis in K562/ADR cells, and its possible mechanism was associated with the intracellular ROS increases.Study on the inhibition effect of MCL on solid tumor cell lines and the combination with Doxorubicin (ADR) by MTT assay, cell cycle and the apoptosis rate by flow cytometry show that MCL was able to inhibit solid tumor cells; The cell cycle was arrested in G2/M with SK-OV-3 and SY5Y cell lines at the concentration of IC50; but not with A549 and CACO-2 cells. The inhibition was strikingly increased with the combination of 10 μM and of MCL and 0.5-8 μM of ADR. The apoptosis rate of HL-60/ADR was increased by 10 μM MCL with 2 μM ADR in a time-dependant manner, which had significant difference with the individual drug.