DACT2 Epigenetic Stimulator Exerts Dual Efficacy for Colorectal Cancer Prevention and Treatment.

DACT2, a tumor suppressor gene in various tumors, is frequently down-regulated via hypermethylation. We found DACT2 gene expressions were dramatically silenced (P = 0.002, n = 8) in our clinical colorectal cancer (CRC) tissues, and TCGA data revealed DACT2 hypermethylation correlated to CRC poor prognosis (P = 0.0129, HR = 0.2153, n = 248). Thus, by screening twelve nutritional compounds, we aimed to find out an effective DACT2 epigenetic stimulator to determine whether DACT2 epigenetic restoration could reverse CRC tumorigenesis. We found that kaempferol significantly increased DACT2 expressions up to 3.47-fold in three CRC cells (HCT116, HT29, and YB5). Furthermore, kaempferol remarkably decreased DACT2 methylation (range: 19.58%-67.00%, P < 0.01), while increased unmethylated DACT2 by 13.72-fold (P < 0.01) via directly binding to DNA methyltransferases DNMT1. By epigenetic reactivating DACT2 transcription, kaempferol notably inhibited nuclear ß-catenin expression to inactivate Wnt/ß-catenin pathway, which consequently restricted CRC cells proliferation and migration. Moreover, in AOM/DSS-induced CRC tumorigenesis, kaempferol-demethylated DACT2 effectively decreased tumor load (range: 50.00%-73.52%, P < 0.05). By determining the chemopreventive and chemotherapeutic efficacy of a novel DACT2 demethylating stimulator, we demonstrated that DACT2 epigenetic restoration could successfully slow down and reverse CRC tumorigenesis.

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.

MicroRNA-92a-3p-mediated inhibition of BCL11A upregulates γ-globin expression and inhibits oxidative stress and apoptosis in erythroid precursor cells.

OBJECTIVE: This study attempted to investigate miR-92a-3p expression in peripheral blood of patients with severe ß-thalassemia, and the effect and action mechanism of miR-92a-3p on γ-globin expression and oxidative stress in erythroid precursor cells. METHODS: CD34+ hematopoietic progenitor cells (HPCs) were isolated from peripheral blood of healthy volunteers and patients with severe ß-thalassemia. The levels of miR-92a-3p, BCL11A, and γ-globin were measured in erythroid precursor cells. High-performance liquid chromatography (HPLC) was used to analyze hemoglobin F (HbF) content. HPCs were induced with erythroid differentiation and erythroid precursor cells were then obtained. The relevance between miR-92a-3p and BCL11A was studied using dual luciferase reporter gene assay, and the correlation between miR-92a-3p and HbF was assayed by Pearson correlation analysis. Reactive oxygen species (ROS), glutathione (GSH), malondialdehyde (MDA), and superoxide dismutase (SOD) in erythroid precursor cells were tested to evaluate oxidative stress. Cell apoptosis was examined by flow cytometry. RESULTS: Remarkably higher expression of miR-92a-3p was observed in erythroid precursor cells. Increased expression of miR-92a-3p resulted in elevated levels of γ-globin, GSH, and SOD, reduced expression of ROS and MDA, and decreased cell apoptosis. BCL11A was identified as a target of miR-92a-3p and to be downregulated by miR-92a-3p. Moreover, BCL11A knockdown alone increased the expression of γ-globin, SOD and GSH, and repressed the levels of ROS and MDA and cell apoptosis, and the following inhibition of miR-92a-3p changed these patterns. CONCLUSIONS: Our data indicated that miR-92a-3p might increase γ-globin level and reduce oxidative stress and apoptosis in erythroid precursor cells by downregulating BCL11A.

Camptosorus sibiricus rupr aqueous extract prevents lung tumorigenesis via dual effects against ROS and DNA damage.

ETHNOPHARMACOLOGICAL RELEVANCE: Camptosorus sibiricus Rupr (CSR) is a widely used herbal medicine with antivasculitis, antitrauma, and antitumor effects. However, the effect of CSR aqueous extract on B[a]P-initiated tumorigenesis and the underlying mechanism remain unclear. Moreover, the compounds in CSR aqueous extract need to be identified and structurally characterized. AIM OF THE STUDY: We aim to investigate the chemopreventive effect of CSR and the underlying molecular mechanism. MATERIALS AND METHODS: A B[a]P-stimulated normal cell model (BEAS.2B) and lung adenocarcinoma animal model were established on A/J mice. In B[a]P-treated BEAS.2B cells, the protective effects of CSR aqueous extract on B[a]P-induced DNA damage and ROS production were evaluated through flow cytometry, Western blot, real-time quantitative PCR, single-cell gel electrophoresis, and immunofluorescence. Moreover, a model of B[a]P-initiated lung adenocarcinoma was established on A/J mice to determine the chemopreventive effect of CSR in vivo. The underlying mechanism was analyzed via immunohistochemistry and microscopy. Furthermore, the new compounds in CSR aqueous extract were isolated and structurally characterized using IR, HR-ESI-MS, and 1D and 2D NMR spectroscopy. RESULTS: CSR effectively suppressed ROS production by re-activating Nrf2-mediated reductases HO-1 and NQO-1. Simultaneously, CSR attenuated the DNA damage of BEAS.2B cells in the presence of B[a]P. Moreover, CSR at 1.5 and 3 g/kg significantly suppressed tumorigenesis with tumor inhibition ratios of 36.65% and 65.80%, respectively. The tumor volume, tumor size, and multiplicity of B[a]P-induced lung adenocarcinoma were effectively decreased by CSR in vivo. After extracting and identifying the compounds in CSR aqueous extract, three new triterpene saponins were isolated and characterized structurally. CONCLUSIONS: CSR aqueous extract prevents lung tumorigenesis by exerting dual effects against ROS and DNA damage, suggesting that CSR is a novel and effective agent for B[a]P-induced carcinogenesis. Moreover, by isolating and structurally characterizing three new triterpene saponins, our study further standardized the quality of CSR aqueous extract, which could widen CSR clinical applications.

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.

Spica prunellae and its marker compound rosmarinic acid induced the expression of efflux transporters through activation of Nrf2-mediated signaling pathway in HepG2 cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Spica prunellae (SP) is a well-known traditional Chinese medicinal herb with properties of antihypertensive, antihyperglycemic, antiviral, anti-inflammatory, and antitumor activities. This herb is also popularly consumed as a food additive in some drinks or other food forms for treating pyreticosis. Rosmarinic acid (RA) is the marker compound from SP, which possesses anti-oxidative and anti-inflammatory functions. AIM OF THE STUDY: This study aims to investigate the regulatory effect of the water extract of SP (WESP) and RA on efflux transports (ETs), including P-glycoprotein (p-gp), multidrug resistance-associated protein 2 (MRP2), and breast cancer resistance protein (BCRP) in HepG2 cell line. Results would provide beneficial information for the proper application of SP in clinics. MATERIALS AND METHODS: HepG2 cells were treated with different doses of the tested drugs for 24 or 96h. MTT assay was used to examine cell viability. The protein and mRNA levels of the ETs were measured by using Western blot and real-time PCR, respectively. Reporter assay was used to study the antioxidant response element (ARE)-luciferin activity by using HepG2-C8 cells, which were generated by transfecting plasmid containing ARE-luciferin gene into HepG2 cells. The transport activities of ETs were tested by using substrate probes. RESULTS: WESP significantly (p<0.05) increased the expression of ETs in a dose-dependent manner. The increase caused by WESP was stronger than RA alone. Both WESP and RA promoted the translocation of nuclear factor E2-related factor-2 (Nrf2) from cytoplasm to the nucleus as well as significantly (p<0.05) enhanced the ARE-luciferin activity. WESP and RA also enhanced the efflux activity of P-gp and MRP2, accompanied by marked increase (p<0.05) in the intracellular ATP levels. CONCLUSIONS: WESP could significantly induce the expression of ETs through the activation of Nrf2-mediated signaling pathway in HepG2 cells. RA could be one of the active compounds responsible for the induction. WESP and RA also enhanced the efflux activity of P-gp and MRP2, and the increased intracellular ATP levels were likely involved in this induction. Results of this study provide a better understanding of the regulation of SP on ETs and the underlying molecular mechanism. Results indicated that potential drug-drug interactions may exist when SP is co-administered with other substrate drugs that are transported via the ETs, especially P-gp and MRP2, thereby providing beneficial information for appropriate use of SP for clinical therapy.

Regulation of drug-metabolizing enzymes and efflux transporters by Astragali radix decoction and its main bioactive compounds: Implication for clinical drug-drug interactions.

ETHNOPHARMACOLOGICAL RELEVANCE: Astragali radix ("Huang Qi" in Chinese, HQ) is a well-known traditional Chinese herbal medicine that possesses various biological functions. Astragaloside IV (AS-IV), calycosin (CS), and formononetin (FMNT) are the three main bioactive compounds of HQ that are responsible for its pharmacological activities and therapeutic efficacy. AIM OF THE STUDY: This study aims to investigate the effects of HQ, AS-IV, CS, and FMNT on major human drug-metabolizing enzymes (DMEs), including CYP3A4, CYP2B6, CYP2E1, UGT1A, UGT1A6, SULT1A1, and SULT1A3, as well as efflux transporters (ETs), including P-gp, MRP2, BCRP, MRP1, and MRP3, by using HepG2 cell line. Results would provide beneficial information for the proper clinical application of HQ. MATERIALS AND METHODS: HepG2 cells were treated with HQ, AS-IV, CS, and FMNT for 96h. Cell viability was examined by MTT assay. The protein and mRNA levels of DMEs and ETs were measured using Western blot and real-time PCR, respectively. RESULTS: Compared with the control group, HQ considerably increased the expression levels of CYP3A4, CYP2B6, CYP2E1, UGT1A, P-gp, MRP2, BCRP, and MRP3 in a dose-dependent manner. Inversely, HQ significantly decreased the protein levels of UGT1A6, SULT1A1, and MRP1. Exposure to AS-IV induced the protein levels of UGT1A, P-gp, MRP1, and MRP3, but produced inhibitory effects on CYP3A4, CYP2B6, and BCRP. The expression levels of CYP3A4, UGT1A, SULT1A1, P-gp, MRP2, and MRP3 were remarkably increased in the CS-treated cells, whereas the protein levels of SULT1A3 and BCRP were decreased. FMNT treatment induced the protein levels towards CYP3A4, CYP2B6, UGT1A, P-gp, MRP1, MRP2, and MRP3, but inhibited the expression of CYP2E1, SULT1A1, and SULT1A3. CONCLUSIONS: HQ and its main bioactive compounds, including AS-IV, CS, and FMNT significantly regulated the expression of the major DMEs and ETs. HQ produced stronger regulations (induction or inhibition) on DMEs and ETs than AS-IV, CS, or FMNT alone. The results indicate that potential drug-drug interactions might exist when the tested drugs, specifically HQ, are co-administered with other substrate drugs that are metabolized or transported via the studied DMEs or ETs. This study provides beneficial information for appropriate use of HQ for clinical therapy.

Artemisinin and its derivatives can significantly inhibit lung tumorigenesis and tumor metastasis through Wnt/ß-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/ß-catenin pathway, and Wnt5a siRNA, we found that ART, DHA, and ARTS could render tumor inhibition partially dependent on Wnt/ß-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 ß-catenin downregulation. In summary, our findings revealed that ART, DHA, and ARTS could suppress lung-tumor progression by inhibiting Wnt/ß-catenin pathway, thereby suggesting a novel target for ART, DHA, and ARTS in cancer treatment.