Preclinical pharmacokinetics and tissue distribution of a novel multikinase inhibitor BZG by validated UPLC-MS/MS assay

A novel multitarget kinase inhibitor BZG with potent anticancer activity in vitro and vivo enhances efficacy of sorafenib through PI3K pathways in hepatocellular carcinoma cells

OBJECTIVES

BZG as a novel multitarget kinase inhibitor, has been proved to inhibit the proliferation of hepatocellular carcinoma (HCC) previously. In this study, we aimed at investigating the underlying mechanisms of BZG with and without sorafenib and evaluating their anti-tumor effects as well as whether BZG could inhibit the activation of phosphoinositide 3-kinase (PI3K)/AKT signaling which is associated with acquired resistance to sorafenib.

METHODS

We evaluated the proliferation of HCC cells by CCK-8 assay and colony formation assay. Cell apoptosis was assessed by Hoechst 33342 staining assay and flow cytometry. Western blot was used to detect the critical enzymes in the PI3K pathways and the expression of p-ERK after BZG alone and combined with sorafenib treatments. Huh-7 hepatocellular carcinoma xenograft model was used to evaluate the anti-carcinoma effects of BZG alone and in combination in vivo. HE staining and TUNEL assay tested the necrosis of tumor tissue and apoptosis of tumor cells.

RESULTS

BZG could inhibit the proliferation of HCC cells in a dose-dependent manner. The combination of BZG and sorafenib produced synergistic effects. PI3K and p-ERK pathway were involved in the anti-tumor functions of BZG alone and when combined with sorafenib. In addition, the combination treatment was seen to be more effective in inhibiting the expression of p-AKT, p-ERK and p-mTOR. Furthermore, Tumor necrosis and cell apoptosis were also observed in Huh-7 hepatocellular carcinoma xenograft models.

CONCLUSIONS

BZG is an attractive agent for treating HCC. The effects of BZG and sorafenib's co-treatment on HCC are more effective than BZG or sorafenib alone.

Pharmacokinetics, tissue distribution and plasma protein binding study of SM-1, a novel PAC-1 derivative

As a PAC-1 derivative, SM-1 exhibts a promising antitumour property. To better understand the relationship between the drug concentrations and pharmacological effects, both liquid chromatography coupled with tandem mass spectrometry and high performance liquid chromatography methods were developed and validated in the work. Those methods were then applied to the pharmacokinetics (PK), tissue distribution and plasma protein binding (PPB) studies of SM-1. As a results, the proposed methods were demonstrated to be accurate, precise and stable for the analysis of the SM-1 in plasma and tissue samples. Meanwhile, the PK parameters of SM-1 showed that SM-1 had good PK properties. SM-1 had good absorption in the body, with 59.01% of the absolute bioavailability in rats and 55.63% of that in dogs. SM-1 rapidly distributed to all tissues, with the highest distribution in the lung and less in the brain and muscle. The PPB rates in rat plasma, dog plasma, and human plasma were 91.1%, 91.2%, and 90.7%, respectively. These good PK properties will contribute SM-1 to be a promising anti-tumour candidate. These results also provide insights into the further pharmacological investigation of SM-1.

Mass spectral analysis of the multikinase inhibitor BZG and its metabolites and analysis of their binding to vascular endothelial growth factor receptor-2

We previously showed that BZG is a novel multitarget kinase inhibitor, which inhibited hepatocellular carcinoma in vivo and in vitro. In the present study, we used ultra-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry (UPLC/Q-TOF MS) to characterize BZG and its metabolites generated in vivo. The probable metabolic mechanism was further confirmed by analysis of Phase I and Phase II metabolism in liver microsomes and with recombinant enzymes. In addition, the binding affinities of BZG metabolites to vascular endothelial growth factor receptor 2 (VEGFR2) were predicted using electronic high throughput screening (eHiTS). The results showed that BZG underwent phase I and phase II metabolism. We detected 11 BZG metabolites and identified hydroxylation, glucuronation, acetylation, sulfonation and degradation as the major metabolic processes in vivo and in vitro. Five of the eleven metabolites showed highly favorable eHiTS energy scores that were lower than sorafenib. Knowledge of the in vivo metabolic pathways of BZG and its binding affinities to VEGFR2 will be beneficial for further clinical development of BZG.