Growth-inhibitory and apoptosis-inducing effects of tanshinones on hematological malignancy cells and their structure-activity relationship.

This study has investigated the growth-inhibitory and apoptosis-inducing effects of dihydrotanshinone, tanshinone I, tanshinone IIA, and cryptotanshinone on hematological malignancy cell lines, aiming to explore their structure-activity relationship. The growth-inhibitory effects of the tanshinones on K562 and Raji cells were assessed using a modified MTT assay; the apoptosis-inducing effects were assessed by fluorescence microscopy and flow cytometry analysis. The changes in cellular morphology were observed using an inverted phase-contrast microscope. MTT results revealed that these tanshinones inhibited cell proliferation in a concentration-dependent and time-dependent manner. The IC50 values of dihydrotanshinone, tanshinone I, tanshinone IIA, and cryptotanshinone for K562 cells were 3.50, 13.52, 19.32, and 47.52 µmol/l at 24 h; 1.36, 4.70, 5.67, and 22.72 µmol/l at 48 h; and 1.15, 1.59, 2.82, and 19.53 µmol/l at 72 h, and the values for Raji cells were 3.30, 4.37, 12.92, and 52.36 µmol/l at 24 h; 1.55, 1.71, 6.54, and 25.45 µmol/l at 48 h; and 1.07, 1.38, 1.89, and 18.47 µmol/l at 72 h. The flow cytometry analysis demonstrated that these tanshinones induced apoptosis of K562 cells in a concentration-dependent manner, and dihydrotanshinone as well as tanshinone I were more potent than tanshinone IIA and cryptotanshinone. Some noticeable apoptotic morphologies could be observed by fluorescence microscopy on tanshinones-treated Raji cells. Collectively, these tanshinones caused growth inhibition and apoptosis in hematological malignancy cell lines, with dihydrotanshinone being the most potent, followed by tanshinone I, tanshinone IIA, and cryptotanshinone. These results suggested that the structure of aromatic ring A enhanced the cytotoxicity and the structure of ring C may have contributed to the cytotoxicity, but the mechanisms need to be further investigated.

[Inhibitory effect of tanshinones on proliferation of K562 cell line and its structure-activity relationship].

The study was purposed to investigate the growth inhibitory effect of tanshinones on K562 cell line and the relationship between their structures and cytotoxicity. The modified MTT assay was adopted to measure the inhibitory effect of tanshinones at different concentrations and chemical structures on K562 cells, and the changes of cell morphology were observed by inverted phase contrast microscopy. The results indicated that the tanshinones could inhibit the proliferation of K562 cells effectively, and their cytotoxicities on K562 cells showed concentration- and time-dependent manners. The IC(50) of dihydrotanshinone I, tanshinone I, tanshinone IIA and cryptotanshinone at 24 hours were 0.91, 4.04, 5.95, 13.85 µg/ml at 48 hours were 0.37, 1.35, 1.71, 6.71 µg/ml; at 72 hours were 0.33, 0.46, 0.82, 6.02 µg/ml, respectively. It is concluded that all of the four tanshinones have proliferation inhibitory effect on K562 cell line, among them the dihydrotanshinone I is the most active one, followed by tanshinone I, tanshinone IIA and cryptotanshinone subsequently, indicating that the chemical structure of aromatic ring A of tanshinones can enhance their cytotoxicity and the structure of furan ring C may influence the cytotoxicity, but their mechanism is still remained to be further investigated.