Linlin Lu

Artemisinin and its derivatives can significantly inhibit lung tumorigenesis and tumor metastasis through Wnt/β-catenin signaling

Non-small-cell lung cancer (NSCLC) is the most prevalent malignancy worldwide given its high incidence, considerable mortality, and poor prognosis. The anti-malaria compounds artemisinin (ART), dihydroartemisinin (DHA), and artesunate (ARTS) reportedly have anti-cancer potential, although the underlying mechanisms remain unclear. In this work, we used flow cytometry to show that ART, DHA, and ARTS could inhibit the proliferation of A549 and H1299 cells by arresting cell cycle in G1 phase. Meanwhile, tumor malignancy including migration, invasion, cancer stem cells, and epithelial–mesenchymal transition were also significantly suppressed by these compounds. Furthermore, ART, DHA, and ARTS remarkably decreased tumor growth in vivo. By using IWP-2, the inhibitor of Wnt/β-catenin pathway, and Wnt5a siRNA, we found that ART, DHA, and ARTS could render tumor inhibition partially dependent on Wnt/β-catenin inactivation. These compounds could strikingly decrease the protein level of Wnt5-a/b and simultaneously increase those of NKD2 and Axin2, ultimately resulting in β-catenin downregulation. In summary, our findings revealed that ART, DHA, and ARTS could suppress lung-tumor progression by inhibiting Wnt/β-catenin pathway, thereby suggesting a novel target for ART, DHA, and ARTS in cancer treatment.

Targeting Tyrosine Kinase Inhibitor-Resistant Non-Small Cell Lung Cancer by Inducing Epidermal Growth Factor Receptor Degradation via Methionine 790 Oxidation

Abstract Aims: Epidermal growth factor receptor (EGFR) tyrosine kinase inhibitors (TKIs) have been developed to treat non-small cell lung cancer (NSCLC) patients with EGFR mutation, but TKI resistance is common. Almost half of the acquired resistance patients are due to additional T790M mutation on EGFR (EGFRT790M), thus overcoming TKI resistance is important. In this study, we aim to investigate the role of reactive oxygen species (ROS) in TKI resistance as well as the molecular and biological effects of EGFRT790M after redox manipulation. Results: The basal ROS levels in EGFRT790M-containing TKI-resistant NSCLC cell lines were substantially high. Sixty-three human lung tumors showed higher NADPH oxidase isoform 2 (NOX2) expression than normal lung tissues, which may contribute to high basal ROS in cancer and poor survival. Interestingly, only NOX3 was upregulated by sanguinarine, a pharmacological agent to elevate ROS, and resulted in EGFR overoxidation, degradation, and apoptosis. By contrast, such responses were lacking in EGFRWT cells. Selective EGFRT790M degradation was manipulated by redox imbalance between NOX3 and methionine reductase A (MsrA). Furthermore, the in vivo tumor suppression effect of sanguinarine, NOX3 upregulation, and EGFR degradation were confirmed. Innovation: We have found a new treatment strategy to overcome TKI resistance by selectively inducing EGFRT790M degradation via specific stimulation of methionine 790 (M790) oxidation. It can be achieved via manipulating redox imbalance between NOX3 and MsrA. Conclusion: Targeting EGFR by elevating ROS and redox imbalance is a potential new strategy to develop a new EGFR inhibitor for TKI-resistant patients with a wide therapeutic window between EGFRT790M and EGFRWT. Antioxid. Redox Signal. 24, 263–279.

Significantly Decreased and More Variable Expression of Major CYPs and UGTs in Liver Microsomes Prepared from HBV-Positive Human Hepatocellular Carcinoma and Matched Pericarcinomatous Tissues Determined Using an Isotope Label-free UPLC-MS/MS Method

PurposeTo determine the liver expression of cytochrome P450 (CYPs) and uridine 5’-diphosphate-glucuronosyltransferases (UGTs), the major phase I and II metabolism enzymes responsible for clearance and detoxification of drugs, xenobiotic and endogenous substances.MethodsA validated isotope label-free method was established for absolute and simultaneous quantification of 9 CYPs (1A2, 2A6, 2B6, 2C8, 2C9, 2C19, 2D, 2E1 and 3A4) and 5 UGTs (1A1, 1A4, 1A6, 1A9 and 2B7) in human liver microsomes using LC-MS/MS.ResultsThe LC-MS/MS method displayed excellent dynamic range (at least 250-fold) and high sensitivity for each of the signature peptides with acceptable recovery, accuracy and precision. The protein expression profile of CYP and UGT isoforms were then determined in match microsomes samples prepared from patients with HBV-positive human hepatocellular carcinoma (HCC). In the tumor microsomes, the average absolute amounts of 8 major CYP isoforms (except CYP2C19) and 3 UGT isoforms (UGT1A1, UGT1A4 and UGT2B7) were decreased significantly (p < 0.05), whereas UGT1A6 and UGT1A9 levels were unchanged (p > 0.05). In addition, among isoforms with altered expression, 6 of 8 CYP isoforms and all three UGT isoforms were much more variable in tumor microsomes. Lastly, the importance of CYP3A4 was greatly diminished whereas the importance of UGT1A6 was enhanced in tumor microsomes.ConclusionThe use of an isotope label-free absolute quantification method for the simultaneous determination of 9 CYPs and 5 UGTs in human liver microsomes reveals that expression levels of CYPs and UGTs in human liver are severely impact by HCC, which could impact drug metabolism, disposition and pharmacotherapy.

Species‐ and gender‐dependent differences in the glucuronidation of a flavonoid glucoside and its aglycone determined using expressed UGT enzymes and microsomes

Flavonoids occur naturally as glucosides and aglycones. Their common phenolic hydroxyl groups may trigger extensive UDP‐glucuronosyltransferase (UGT)‐ catalysed metabolism. Unlike aglycones, glucosides contain glucose moieties. However, the influence of these glucose moieties on glucuronidation of glucosides and aglycones remains unclear. In this study, the flavonoid glucoside tilianin and its aglycone acacetin were used as model compounds. The glucuronidation characteristics and enzyme kinetics of tilianin and acacetin were compared using human UGT isoforms, liver microsomes and intestinal microsomes obtained from different animal species. Tilianin and acacetin were metabolized into different glucuronides, with UGT1A8 produced as the main isoform. Assessment of enzyme kinetics in UGT1A8, human liver microsomes and human intestinal microsomes revealed that compared with tilianin, acacetin displayed lower Km (0.6‐, 0.7‐ and 0.6‐fold, respectively), higher Vmax (20‐, 60‐ and 230‐fold, respectively) and higher clearance (30‐, 80‐ and 300‐fold, respectively). Furthermore, glucuronidation of acacetin and tilianin showed significant species‐ and gender‐dependent differences. In conclusion, glucuronidation of flavonoid aglycones is faster than that of glucosides in the intestine and the liver. Understanding the metabolism and species‐ and gender‐dependent differences between glucosides and aglycones is crucial for the development of drugs from flavonoids. Copyright

Severely Impaired and Dysregulated Cytochrome P450 Expression and Activities in Hepatocellular Carcinoma: Implications for Personalized Treatment in Patients

This study aims to systematically determine the activities and expressions of cytochrome P450s (CYP) in hepatocellular carcinoma (HCC) patients to support their optimal use in personalized treatment of HCC. Activities of seven major drug-metabolizing CYP enzymes (CYP1A2, 2A6, 2C8, 2C9, 2D6, 2E1, and 3A4) were determined in tumors and pericarcinomatous tissues harvested from 26 patients with hepatitis B virus-positive HCC using probe substrates. Protein and mRNA levels of these CYPs were also measured using isotope label-free LC/MS-MS method and real-time PCR, respectively. Maximal metabolic velocity (Vmax) of CYP probe substrates was decreased by 2.5- to 30-fold in tumor microsomes, accompanied by a corresponding decrease in their protein and mRNA expression levels. However, Km values and turnover numbers of substrates in tumor microsomes were not changed. High correlations between activities and CYP protein levels were also observed, but the correlation between activities and mRNA levels was often poor. There was a major decrease in the degree of correlation in CYP expression in tumor tissues, suggesting that CYP expression levels are greatly disrupted by the tumorigenic process. Our unprecedented systemic study of the effects of HCC on CYPs demonstrated that activities of CYPs were seriously impaired and their expression patterns were severely altered by HCC. We proposed that determination of the CYP protein expression profile by LC/MS-MS in each patient is a promising approach that can be clinically used for individualized treatment of HCC. Mol Cancer Ther; 14(12); 2874–86. ©2015 AACR.

Multidrug resistance-associated protein 2 is involved in the efflux of Aconitum alkaloids determined by MRP2-MDCKII cells

AIMS Aconitum alkaloids mainly contain highly toxic aconitine (AC), mesaconitine (MA), and hypaconitine (HA) and less toxic benzoylaconine (BAC), benzoylmesaconine (BMA), benzoylhypaconine (BHA), aconine, mesaconine, and hypaconine. The efflux transporters including P-glycoprotein (P-gp), breast cancer resistance protein (BCRP) and multidrug resistance-associated protein 2 (MRP2) can efflux toxicants to prevent poisoning. Our previous publication has proved that P-gp and BCRP contributed to the efflux of AC, MA and HA, which is demonstrated in the human colonic adenocarcinoma cell lines (Caco-2 cells), Mardin-Darby canine kidney cell lines transfected with MDR1 or BCRP (MDR1-MDCKII and BCRP-MDCKII cells). However, the role of MRP2 remains uncertain. MAIN METHODS The MRP2-MDCKII cells were used to determine the efflux ratios (Er) and intracellular amounts of Aconitum alkaloids. In addition, the importance of MRP2 was further investigated with or without the MRP2 inhibitor, LTC4. KEY FINDINGS The Er values of AC, MA, HA, BAC, BMA and BHA in MRP2-MDCKII cells (6.4 ± 0.3, 5.9 ± 0.5, 2.2 ± 0.2, 1.6 ± 0.3, 1.7 ± 0.2 and 1.9 ± 0.2 respectively) were significantly higher than those in MDCKII cells, which were close to 1. In the presence of LTC4, the Er values of AC, MA, HA, BAC, BMA and BHA were reduced to approximately 1 and their intracellular amounts were also significantly increased in MRP2-MDCKII cells. SIGNIFICANCE MRP2 was involved in the efflux of AC, MA, HA, BAC, BMA and BHA, which would be useful for the safe application of these components or their herbs.

Coadministration of Pinellia ternata Can Significantly Reduce Aconitum carmichaelii to Inhibit CYP3A Activity in Rats

Chuanwu (CW), the mother root of Aconitum carmichaelii Debx., is a traditional Chinese medicine (TCM) for treating traumatic injuries, rheumatoid arthritis, and tumors. CW coadministered with banxia (BX), the root of Pinellia ternata, is also widely prescribed in clinical practice. However, the mechanism of this combination is yet deciphered. Current study aimed to investigate the effects of CW, including raw chuanwu (RCW) and processed chuanwu (PCW) alone, as well as CW coadministered with BX on CYP3A activity. Buspirone (BP) and testosterone (Tes) were used as specific probe substrates in vivo and ex vivo, respectively. CYP3A activity was determined by the metabolites formation ratios from the substrates. Compared with those in the control group, the metabolites formation ratios significantly decreased in the RCW and PCW alone groups, accompanied by a marked decrease in CYP3A protein and mRNA levels. However, there was a significant increase in those ratios in the RCW-BX and PCW-BX groups compared to the RCW and PCW alone groups. The results indicated that both RCW and PCW can inhibit CYP3A activity in rats because of downregulation of CYP3A protein and mRNA levels. Decreases in CYP3A activity can be reversed by coadministration with BX.

Induction of P-glycoprotein expression and activity by Aconitum alkaloids: Implication for clinical drug–drug interactions

The Aconitum species, which mainly contain bioactive Aconitum alkaloids, are frequently administered concomitantly with other herbal medicines or chemical drugs in clinics. The potential risk of drug–drug interactions (DDIs) arising from co-administration of Aconitum alkaloids and other drugs against specific targets such as P-glycoprotein (P-gp) must be evaluated. This study focused on the effects of three representative Aconitum alkaloids: aconitine (AC), benzoylaconine (BAC), and aconine, on the expression and activity of P-gp. We observed that Aconitum alkaloids increased P-gp expression in LS174T and Caco-2 cells in the order AC > BAC > aconine. Nuclear receptors were involved in the induction of P-gp. AC and BAC increased the P-gp transport activity. Strikingly, intracellular ATP levels and mitochondrial mass also increased. Furthermore, exposure to AC decreased the toxicity of vincristine and doxorubicin towards the cells. In vivo, AC significantly up-regulated the P-gp protein levels in the jejunum, ileum, and colon of FVB mice, and protected them against acute AC toxicity. Taken together, the findings of our in vitro and in vivo experiments indicate that AC can induce P-gp expression, and that co-administration of AC with P-gp substrate drugs may cause DDIs. Our findings have important implications for Aconitum therapy in clinics.

Novel histone deacetylase inhibitors derived from Magnolia officinalis significantly enhance TRAIL-induced apoptosis in non-small cell lung cancer.

Histone modifications play critical roles in the progression of non-small cell lung cancer (NSCLC), which accounts for almost 85% of all diagnosed lung cancers. Magnolol and polyphenol mixture (PM) derived from Magnolia officinalis exhibited remarkable antitumor activities in lung cancer. However, the epigenetic effects and molecular mechanisms of magnolol and PM in NSCLC have yet to be reported. In this study, the epigenetic effects of magnolol and PM in NSCLC were examined in vitro and in vivo. Results revealed that magnolol and PM significantly suppressed the expression levels and function of class I histone deacetylases (HDACs). In A549 and H1299 cells, magnolol and PM remarkably induced cell apoptosis by arresting the cell cycle in the G0/G1 phase while simultaneously activating various pro-apoptotic signals, including TRAIL-R2 (DR5), Bax, caspase 3, cleaved caspase 3, and cleaved PARP. However, these apoptosis-promoting effects could be attenuated by TSA, which is a specific class I HDACs inhibitor. ChIP assays also demonstrated that magnolol and PM significantly enriched the histone acetyl mark (H3K27ac) in the promoter region of DR5. In A549 xenograft model, magnolol and PM notably reduced tumor growth by 44.40% and 35.40%, respectively. Therefore, magnolol and PM, as potential inhibitors of class I HDACs, induced tumor cell apoptosis and suppressed tumor growth partially by epigenetically activating DR5, which is a key protein in death receptor signaling pathway.

SGLT-1 Transport and Deglycosylation Inside Intestinal Cells are Key Steps in the Absorption and Disposition of Calycosin-7-O-β-D-Glucoside in Rats

Hydrolysis by lactase-phloridzin hydrolase (LPH) is the first and critical step in the absorption of isoflavonoid glucosides. However, the absorption characteristics of calycosin-7-O-β-d-glucoside (CG) slightly differ from other isoflavonoid glucosides. In this study, we used the rat intestinal perfusion model and performed pharmacokinetic studies and in vitro experiments to determine the factors influencing CG absorption and disposition. After oral administration of isoflavonoid glucosides, LPH was found to play minimal or no role on the hydrolysis of CG, in contrast to that of daidzin. CG was mainly transported into the small intestinal cells by sodium-dependent glucose transporter 1 (SGLT-1) as intact. This pathway could be the main mechanism underlying the high permeability of CG in the small intestine. CG was likely to be hydrolyzed in enterocytes to its aglycone calycosin by broad-specific β-glucuronides (BSβG) and glucocerebrosidase or rapidly metabolized. Calycosin was also rapidly and extensively metabolized to 3′-glucuronide in the enterocytes and liver, and the glucuronidation rates of calycosin and CG were much higher in the former. The metabolites were also transported into lumen by breast cancer resistance protein and multidrug resistance-associated protein 2. In conclusion, the enterocytes could be an important site for CG absorption, deglycosylation, and metabolism in rats. This study could contribute to the theoretical foundation and mechanism of absorption and disposition of flavonoid compounds.