Discovery of Leonuri and therapeutical applications: From bench to bedside

Leonurine Promotes Cisplatin Sensitivity in Human Cervical Cancer Cells Through Increasing Apoptosis and Inhibiting Drug-Resistant Proteins

BACKGROUND

Cisplatin-based neoadjuvant chemotherapy and concurrent radiotherapy and chemotherapy are the main treatment for advanced cervical cancer. However, the development of multidrug resistance (MDR) leads to chemotherapy failure, tumor recurrence and poor survival. In this research, we investigated the effect and corresponding mechanism of leonurine on cisplatin sensitivity of cervical cancer cells.

METHODS

Anti-cervical cancer efficacy of leonurine and leonurine combined with cisplatin was examined in C33A and Ms751 cells. The cell counting kit-8 assay and bromodeoxyuridine assay were applied for measuring cell proliferation. CompuSyn software was used to calculate the combination index and assess the synergistic effect of leonurine and cisplatin on cell proliferation. The cell cycle distribution and cell apoptosis were analyzed by flow cytometry. The expression of cleaved caspase-3, poly ADP-ribose polymerase (PARP), B-cell lymphoma-2 associated X (BAX), B-cell lymphoma-2 (BCL-2), P glycoprotein (P-Gp) protein and multiple drug resistance protein 1 (MRP1) was analyzed by Western blotting.

RESULTS

Leonurine had time- and dose-dependent anti-proliferative effects on C33A and MS751 cells. Leonurine and cisplatin combination was more efficacious in inhibiting the growth of cervical cancer cells than either of the two drugs. The combined application has shown that the cervical cancer cells were arrested at G1 phase after treatments. Moreover, flow cytometry analysis indicated that the combined treatment could cause more cell apoptosis than the single drug treatment. Consistently, combined treatment elevated BAX/BCL-2 ratio, and the expression of BAX, PARP and cleaved caspase-3 proteins. Mechanistic investigations uncovered that the tumor-inhibiting effects of the co-treatment were mediated by repressing MDR, including MRP1 and P-Gp protein, thereby enhancing the efficiency of cisplatin.

CONCLUSION

Leonurine and cisplatin have synergistic antitumorigenic effects on cervical cancer. Combination with leonurine may serve as a novel strategy for enhancing cisplatin sensitivity via the inhibition of the expression of MRP1 and P-Gp.

CYP2A13 Acts as the Main Metabolic CYP450s Enzyme for Activating Leonurine in Human Bronchial Epithelial Cells

Background

Leonurine is an active component of the traditional Chinese medicine Leonurus japonicus. This study aimed to investigate the effects of overexpressed CYP450s on the metabolic activity of leonurine.

Material/Methods

BEAS-2B cells stably expressing CYP1A1, 1A2, 2A13, 2B6, and 3A4 were constructed. CYP450s expression was identified using reverse-transcription PCR and Western blot assay. CCK-8 assay was used to evaluate the effect of leonurine on cell activity. Leonurine was incubated in vitro with CYP1A1, 1A2, 2A13, 2B6, and 3A4 metabolic enzymes to evaluate the clearance rate of CYP450 enzymes for leonurine. UPLC-MS was used to detect changes of drug concentration and discover the main metabolic enzymes affecting leonurine.

Results

BEAS-2B cells stably expressing CYP1A1, 1A2, 2A13, 2B6, and 3A4 were successfully constructed. According to primary mass spectra and secondary mass spectra of leonurine, the main metabolic enzymes were 312.1550 [H+] and 181.0484. Compared to the control group, residue of leonurine in CYP2A13 group was significantly reduced (F=5.307, p=0.024). Compared to the 0-min group, the clearance rate of leonurine in the CYP2A13-treated group was significantly decreased at 120 min after treatment (F=7.273, p=0.007). CCK-8 results also showed that activity of BEAS-2B cells that overexpress CYP2A13 gradually decreased with increased concentration of leonurine. Although CYP2A13 demonstrated good metabolic activity for leonurine, we found that CYP1A1, 1A2, 2B6, and 3A4 had no metabolic effects on leonurine.

Conclusions

Leonurine can be effectively activated through CYP2A13 enzyme metabolism, and further inhibits activity of human lung epithelial cells (BEAS-2B). Therefore, CYP2A13 is a main metabolic enzyme for leonurine in BEAS-2B cells.

Identification of the absorbed components and their metabolites of Tianma-Gouteng granule in rat plasma and bile using ultra-high-performance liquid chromatography combined with quadrupole time-of-flight mass spectrometry

Tianma-Gouteng granule (TGG), a Chinese herbal formula preparation, is clinically used for the treatment of cardio-cerebrovascular diseases such as hypertension, cerebral ischaemia, acute ischaemic stroke and Parkinson's disease. Although few reports have been published concerning the absorbed prototype components of TGG, the possible metabolic pathways of TGG in vivo remain largely unclear. In this study, a method using UPLC-Q/TOF MS was established for the detection and identification of the absorbed prototype components and related metabolites in rat plasma and bile after oral administration of TGG at high and normal clinical dosages. A total of 68 components were identified or tentatively identified in plasma and bile samples, including absorbed prototypes and their metabolites. The major absorbed components were gastrodin, isorhynchophylline, rhynchophylline, isocorynoxeine, corynoxeine, geissoschizine methyl ether baicalin, baicalein, wogonoside, wogonin, geniposidic acid, leonurine, 2,3,5,4'-tetrahydroxystilbene-2-O-β-d-glucoside and emodin. The main metabolic pathways of these components involved phase I (isomerization, hydrolysis and reduction) and phase II (glucuronidation and sulfation) reaction, and the phase II biotransformation pathway was predominant. The present study provides rich information on the in vivo absorption and metabolism of TGG, and the results will be helpful for further studies on the pharmacokinetics and pharmacodynamics of TGG.