Cabozantinib reverses multidrug resistance of human hepatoma HepG2/adr cells by modulating the function of P-glycoprotein.

BACKGROUND & AIMS: Cabozantinib, a small-molecule multitargeted tyrosine kinase inhibitor, has entered into a phase III clinical trial for the treatment of hepatocellular carcinoma (HCC). This study assessed the mechanistic effect of cabozantinib on the reversal of P-glycoprotein (P-gp)-mediated multidrug resistance (MDR). METHODS: CCK-8 assays and tumour xenografts were used to investigate the reversal of MDR in vitro and in vivo respectively. Substrate retention assays were evaluated by fluorescence microscope and flow cytometry. Western blotting was used to detect protein expression levels. mRNA expression was determined by qPCR. The ATPase activity of P-gp was investigated using Pgp-Glo(™) assay systems. The binding mechanism of cabozantinib to P-gp at the molecular level was evaluated using docking analysis. RESULTS: Cabozantinib enhanced the cytotoxicity of P-gp substrate drugs in HepG2/adr and HEK293-MDR1 cells but had no effect on non-P-gp substrates. In addition, cabozantinib increased the accumulation of P-gp substrates in HepG2/adr cells but had no effect in HepG2 cells. Furthermore, cabozantinib did not alter the expression of P-gp mRNA or protein but did stimulate the activity of P-gp ATPase. The docking study indicated that cabozantinib and verapamil may partially share a binding site on P-gp. The reversal concentrations of cabozantinib did not affect the expression of MET, AKT and ERK1/2. Significantly, cabozantinib increased the inhibitory efficacy of doxorubicin in P-gp-overexpressing HepG2/adr cell xenografts in nude mice. CONCLUSION: Cabozantinib reverses P-gp-mediated MDR by directly inhibiting the efflux function of P-gp, indicating that cabozantinib may help to reverse P-gp-mediated MDR in HCC and other cancer chemotherapy.

Application of Transparent Cap-assisted Choledochoscopy in Endoscopic Gallbladder-preserving Surgery.

BACKGROUND: The gold standard treatment for cholecystolithiasis is laparoscopic cholecystectomy. However, the complications of cholecystectomy have led to adoption of gallbladder-preserving surgery. The study was to investigate significance of transparent cap-assisted choledochoscopy in gallbladder-preserving surgery. MATERIALS AND METHODS: This is a retrospective study of patients who underwent gallbladder-preserving surgery by laparoscopic choledochoscopy along with choledochoscopy with or without a transparent cap from January 2018 to September 2018 in our hospital. The differences in the duration of gallbladder exploration, surgical complications, adverse events, and the recurrence of stones within 6 months after surgery were compared between 2 groups. RESULTS: Fifty patients underwent laparoscopic choledochoscopy along with choledochoscopy without transparent cap (Group A), while 50 patients underwent laparoscopic along with transparent cap-assisted choledochoscopy (Group B). Gallbladder exploration time was 27.96±12.24 minutes in Group A, and 12.04±6.01 minutes in Group B. One case had stone recurrence within 6 months in Group B, while 8 cases had stone recurrence in group A. CONCLUSIONS: Comparing with laparoscope combined with choledochoscopy, transparent cap-assisted choledochoscopy has advantages in gallbladder-preserving surgery.

Activation of MET promotes resistance to sorafenib in hepatocellular carcinoma cells via the AKT/ERK1/2-EGR1 pathway.

Sorafenib is an oral multikinase inhibitor that has become an established therapeutic approach in advanced hepatocellular carcinoma (HCC). However, the benefit of sorafenib in clinical therapy is often affected by drug resistance. Therefore, it is important to explore the mechanisms underlying sorafenib resistance and to develop individualized therapeutic strategies for coping with this problem. In this study, we found that addition of HGF to sorafenib-treated HCC cells activated MET and re-stimulated the downstream AKT and ERK1/2 pathways. Thereby, restored sorafenib-treated HCC cells proliferation, migration and invasion ability, and rescued cells from apoptosis. In addition, we found that HGF treatment of HCC cells induced early growth response protein (EGR1) expression, which is involved in sorafenib resistance. Importantly, the HGF rescued effect in sorafenib-treated HCC cells could be abrogated by inhibiting MET activation with PHA-665752 or by downregulating EGR1 expression with small interfering RNA (siRNA). Therefore, inhibition of the HGF/MET pathway may improve response to sorafenib in HCC, and combination therapy should be further investigated.

Specific lipase-responsive polymer-coated gadolinium nanoparticles for MR imaging of early acute pancreatitis.

Currently, available methods for diagnosis of acute pancreatitis (AP) are mainly dependent on serum enzyme analysis and imaging techniques that are too low in sensitivity and specificity to accurately and promptly diagnose AP. The lack of early diagnostic tools highlights the need to search for a highly effective and specific diagnostic method. In this study, we synthesized a conditionally activated, gadolinium-containing, nanoparticle-based MRI nanoprobe as a diagnostic tool for the early identification of AP. Gadolinium diethylenetriaminepentaacetic fatty acid (Gd-DTPA-FA) nanoparticles were synthesized by conjugation of DTPA-FA ligand and gadolinium acetate. Gd-DTPA-FA exhibited low cytotoxicity and excellent biocompatibility when characterized in vitro and in vivo studies. L-arginine induced a gradual increase in the intensity of the T1-weighted MRI signal from 1 h to 36 h in AP rat models. The increase in signal intensity was most significant at 1 h, 6 h and 12 h. These results suggest that the Gd-DTPA-FA as an MRI contrast agent is highly efficient and specific to detect early AP.

Effect of BIBF 1120 on reversal of ABCB1-mediated multidrug resistance.

BACKGROUND: The overexpression of ATP-binding cassette (ABC) transporters is one of the main causes of multi-drug resistance (MDR) which represents a major obstacle to the success of cancer chemotherapy. In this study, we examined the effect of BIBF 1120, an inhibitor of vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptors (PDGFRs) and fibroblast growth factor receptors (FGFRs) tyrosine kinases, on the reversal of multidrug resistance in vitro. METHODS: The doxorubicin and rhodamine 123 retention assay was performed by flowcytometry. Western blot were employed to identify ABCB1 expression level and the effect of BIBF 1120 on the blockade of Akt and ERK1/2 phosphorylation. The expression of mdr1 mRNA was determined by RT-PCR analysis. The ATPase activity of ABCB1 was investigated using Pgp-Glo™ assay systems. RESULTS: BIBF 1120 significantly enhanced the cytotoxicity of doxorubicin and paclitaxel and increased the accumulation of ABCB1 substrates in ABCB1-overexpressing cancer cells, whereas it had no effect on the parental cells. On the other hand, BIBF 1120 did not alter the cytotoxicity of non-ABCB1 substrates and was unable to reverse ABCC1 or ABCG2-mediated MDR. Furthermore, BIBF 1120 inhibited the ATPase activity of ABCB1 in a concentration-dependent manner. However, no detectable alteration on the expression level of mdr1 mRNA or ABCB1 protein was identified in ABCB1-overexpressing cancer cells by different treatments of BIBF 1120. Interestly, total and phosphorylated forms of AKT and ERK1/2 were not inhibited by BIBF 1120 at the reversal concentrations. CONCLUSION: Our results suggest that BIBF 1120 is capable of overcoming ABCB1-mediated drug resistance by inhibiting ABCB1 function, which may have clinical significance for BIBF 1120 combinational treatment of certain resistant cancers.