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.

Better performance of PIVKA-II for detecting hepatocellular carcinoma in patients with chronic liver disease with normal total bilirubin.

BACKGROUND: Serum protein induced by vitamin K absence or antagonist-II (PIVKA-II) is a promising biomarker for hepatocellular carcinoma (HCC) surveillance. AIM: To identify the contributing factors related to the abnormal elevation of PIVKA-II level and assess their potential influence on the performance of PIVKA-II in detecting HCC. METHODS: This study retrospectively enrolled in 784 chronic liver disease (CLD) patients and 267 HCC patients in Mengchao Hepatobiliary Hospital of Fujian Medical University from April 2016 to December 2019. Logistic regression and the area under the receiver operating characteristic curve (AUC) were used to evaluate the influencing factors and diagnostic performance of PIVKA-II for HCC, respectively. RESULTS: Elevated PIVKA-II levels were independently positively associated with alcohol-related liver disease, serum alkaline phosphatase (ALP), and total bilirubin (TBIL) for CLD patients and aspartate aminotransferase (AST) and tumor size for HCC patients (all P < 0.05). Serum PIVKA-II were significantly lower in patients with viral etiology, ALP ≤ 1 × upper limit of normal (ULN), TBIL ≤ 1 × ULN, and AST ≤ 1 × ULN than in those with nonviral disease and abnormal ALP, TBIL, or AST (all P < 0.05), but the differences disappeared in patients with early-stage HCC. For patients with TBIL ≤ 1 × ULN, the AUC of PIVKA-II was significantly higher compared to that in patients with TBIL > 1 × ULN (0.817 vs 0.669, P = 0.015), while the difference between ALP ≤ 1 × ULN and ALP > 1 × ULN was not statistically significant (0.783 vs 0.729, P = 0.398). These trends were then more prominently perceived in subgroups of patients with viral etiology and HBV alone. CONCLUSION: Serum PIVKA-II has better performance in detecting HCC at an early stage for CLD patients with normal serum TBIL.

Chimeric STAR receptors using TCR machinery mediate robust responses against solid tumors.

Chimeric antigen receptor T (CAR-T) cell therapies have demonstrated high response rate and durable disease control for the treatment of B cell malignancies. However, in the case of solid tumors, CAR-T cells have shown limited efficacy, which is partially attributed to intrinsic defects in CAR signaling. Here, we construct a double-chain chimeric receptor, termed as synthetic T cell receptor (TCR) and antigen receptor (STAR), which incorporates antigen-recognition domain of antibody and constant regions of TCR that engage endogenous CD3 signaling machinery. Under antigen-free conditions, STAR does not trigger tonic signaling, which has been reported to cause exhaustion of traditional CAR-T cells. Upon antigen stimulation, STAR mediates strong and sensitive TCR-like signaling, and STAR-T cells exhibit less susceptibility to dysfunction and better proliferation than traditional 28zCAR-T cells. In addition, STAR-T cells show higher antigen sensitivity than CAR-T cells, which holds potential to reduce the risk of antigen loss-induced tumor relapse in clinical use. In multiple solid tumor models, STAR-T cells prominently outperformed BBzCAR-T cells and generated better or equipotent antitumor effects to 28zCAR-T cells without causing notable toxicity. With these favorable features endowed by native TCR-like signaling, STAR-T cells may provide clinical benefit in treating refractory solid tumors.

Novel Curcumin Liposome Modified with Hyaluronan Targeting CD44 Plays an Anti-Leukemic Role in Acute Myeloid Leukemia in Vitro and in Vivo.

Curcumin has been widely used as a food additive for centuries and has been recently explored for its anti-inflammatory and antitumor properties. Although curcumin is pharmacologically safe and efficacious to certain cancers, its role against acute myeloid leukemia (AML) still remains unclear, and it lacks clinical application due to low water solubility and low in vivo bioavailability. To address these issues, we developed a novel curcumin liposome modified with hyaluronan (HA-Cur-LPs) to specifically deliver curcumin to AML by targeting CD44 on AML cell surface. When compared with free curcumin and nontargeted liposome (Cur-LPs), the HA-Cur-LPs exhibited good stability, high affinity to CD44, increased cellular uptake, and more potent activity on inhibiting AML cell proliferation. The KG-1 cell implanted AML mice had significantly delayed, or even prevented, AML progression following treatment with 50 mg/kg of curcumin dose in the HA-Cur-LPs every 2 days for 2 weeks. Mechanistically, the anti-AML effects of HA-Cur-LPs were achieved by inhibiting Akt/ERK pathways and activating caspase-dependent apoptosis. Moreover, HA-Cur-LPs played a critical role in downregulation of DNMT1 expression in AML, leading to DNA hypomethylation and reactivation of tumor suppressor genes such as miR-223. The development and assessment of the HA-Cur-LPs in this study provide another potential choice for AML therapy, using HA-Cur-LPs as either a single treatment agent or in combination with other treatments.