Pharmacokinetics, tissue distribution, and plasma protein binding rate of curcumol in rats using liquid chromatography tandem mass spectrometry.

Objective: Curcumol is one of the major active ingredients isolated from the traditional Chinese medicine Curcumae Rhizoma and is reported to exhibit various bioactivities, such as anti-tumor and anti-liver fibrosis effects. However, studies of curcumol pharmacokinetics and tissue distribution are currently lacking. This study aims to characterize the pharmacokinetics, tissue distribution, and protein binding rate of curcumol. Methods: Pharmacokinetics properties of curcumol were investigated afte doses of 10, 40, and 80 mg/kg of curcumol for rats and a single dose of 2.0 mg/kg curcumol was given to rats via intravenous administration to investigate bioavailability. Tissue distribution was investigated after a single dose of 40 mg/kg of orally administered curcumol. Plasma protein binding of curcumol was studied in vitro via the rapid equilibrium dialysis system. Bound and unbound curcumol in rat plasma were analyzed to calculate the plasma protein binding rate. A UHPLC-MS/MS method was developed and validated to determine curcumol in rat plasma and tissues and applied to study the pharmacokinetics, tissue distribution, and plasma protein binding in rats. Results: After oral administration of 10, 40, and 80 mg/kg curcumol, results indicated a rapid absorption and quick elimination of curcumol in rats. The bioavailability ranging from 9.2% to 13.1% was calculated based on the area under the curves (AUC) of oral and intravenous administration of curcumol. During tissue distribution, most organs observed a maximum concentration of curcumol within 0.5-1.0 h. A high accumulation of curcumol was found in the small intestine, colon, liver, and kidney. Moreover, high protein binding rates ranging from 85.6% to 93.4% of curcumol were observed in rat plasma. Conclusion: This study characterized the pharmacokinetics, tissue distribution, and protein binding rates of curcumol in rats for the first time, which can provide a solid foundation for research into the mechanisms of curcumol's biological function and clinical application.

Circular RNA 100146 functions as an oncogene through direct binding to miR-361-3p and miR-615-5p in non-small cell lung cancer.

Circular RNAs are widely expressed in eukaryotic cells and associated with cancer. However, limited studies to date have focused on the potential role of circRNAs in progression of lung cancer. Data from the current investigation showed that circRNA 100146 is highly expressed in non-small cell lung cancer (NSCLC) cell lines and the chemically induced malignant transformed bronchial cell line, 16HBE-T, as well as 40 paired tissue samples of NSCLC. Suppression of circRNA 100146 inhibited the proliferation and invasion of cells and promoted apoptosis. Furthermore, circRNA 100146 could interact with splicing factors and bind miR-361-3p and miR-615-5p to regulate multiple downstream mRNAs. Our collective findings support a role of circRNA 100146 in the development of NSCLC and further demonstrate endogenous competition among circRNA 100146, SF3B3 and miRNAs, providing novel insights into the mechanisms underlying non-small cell lung cancer.

Silencing of lncRNA AFAP1-AS1 suppressed lung cancer development by regulatory mechanism in cis and trans.

Although the long noncoding RNA AFAP1-AS1 has been shown to be involved in various types of cancer, its involvement in lung cancer remains poorly understood. In the current study, we found that AFAP1-AS1 was substantially over expressed in lung cancer tissues and cell lines. In addition, AFAP1-AS1 expression level was proven to be associated with the malignant features of lung cancer. Knockdown of AFAP1-AS1 significantly suppressed cell proliferation by increasing cell apoptosis and G0/G1 phase retardation of cell cycle in lung cancer cells. Furthermore, AFAP1-AS1 knockdown could suppress tumor growth of lung cancer in BALB/c nude mice. We also identified that AFAP1-AS1 silencing could influence the expression of AFAP1 and KRT1 on mRNA and protein level by cis and trans regulatory mechanism. Moreover, the oncogenic activities of AFAP1-AS1 on cell proliferation are partially mediated by KRT1. In summary, these findings demonstrate that AFAP1-AS1 plays an essential role in promoting lung cancer development in vitro and vivo. It indicated that AFAP1-AS1 is a promising prognostic predictor for patients with lung cancer.

Diosmetin protects against retinal injury via reduction of DNA damage and oxidative stress.

Visual impairment is a global public health problem that needs new candidate drugs. Chrysanthemum is a traditional Chinese drug, famous for its eye-protective function, with an unclear mechanism of action. To determine how chrysanthemum contributes to vision, we identified, for the first time, the component of chrysanthemum, diosmetin (DIO), which acts in protecting the injured retina in an adriamycin (ADR) improving model. We observed that DIO could attenuate the apoptosis of retinal cells in Sprague-Dawley rats and verified this effect in cultured human retinal pigment epithelium (RPE) cells, ARPE-19. Our further study on the mechanism revealed the counteractive effect of DIO on the attenuation of DNA damage and oxidative stress, which occurs in a wide range of retinal disorders. These results collectively promise the potential value of DIO as a retinal-protective agent for disorders that lead to blindness. In addition, we identified, for the first time, the component of chrysanthemum, DIO, which acts in protecting the injured retina.

A novel long noncoding RNA AK001796 acts as an oncogene and is involved in cell growth inhibition by resveratrol in lung cancer.

Lung cancer is the most common form of cancer throughout the world. The specific targeting of long noncoding RNAs (lncRNAs) by resveratrol opened a new avenue for cancer chemoprevention. In this study, we found that 21 lncRNAs were upregulated and 19 lncRNAs were downregulated in lung cancer A549 cells with 25 µmol/L resveratrol treatment determined by microarray analysis. AK001796, the lncRNA with the most clearly altered expression, was overexpressed in lung cancer tissues and cell lines, but its expression was downregulated in resveratrol-treated lung cancer cells. By monitoring cell proliferation and growth in vitro and tumor growth in vivo, we observed a significant reduction in cell viability in lung cancer cells and a slow growth in the tumorigenesis following AK001796 knockdown. We also found that AK001796 knockdown caused a cell-cycle arrest, with significant increases in the percentage of cells in G0/G1 in lung cancer cells. By using cell cycle pathway-specific PCR arrays, we detected changes in a number of cell cycle-related genes related to lncRNA AK001796 knockdown. We further investigated whether AK001796 participated in the anticancer effect of resveratrol and the results showed that reduced lncRNA AK001796 level potentially impaired the inhibitory effect of resveratrol on cell proliferation. To our knowledge, this is the first study to report the changes in an lncRNA expression profile induced by resveratrol in lung cancer.

Autophagy protects against dasatinib-induced hepatotoxicity via p38 signaling.

Liver dysfunction is a common side effect associated with the treatment of dasatinib and its mechanism is poorly understood. Autophagy has been thought to be a potent survival or death factor for liver dysfunction, which may shed the light on a novel strategy for the intervention of hepatotoxicity caused by dasatinib. In this study, we show for the first time that autophagy is induced, which is consistent with the formation of liver damage. Autophagy inhibition exacerbated dasatinib-induced liver failure, suggesting that autophagy acted as a self-defense mechanism to promote survival. Oxidative stress has been shown to be an important stimulus for autophagy and hepatotoxicity. Interestingly, dasatinib increased the activity of p38, which is a critical modulator of the oxidative stress related to liver injury and autophagy. p38 silencing significantly blocked LC3-II induction and p62 reduction by dasatinib, which was accompanied by increased caspase-3 and PARP cleavage, indicating that autophagy alleviated dasatinib-induced hepatotoxicity via p38 signaling. Finally, the p38 agonist isoproterenol hydrochloride (ISO) alleviated dasatinib-induced liver failure by enhancing autophagy without affecting the anticancer activity of dasatinib. Thus, this study revealed that p38-activated autophagy promoted survival during liver injury, which may provide novel approaches for managing the clinical applications of dasatinib.

Dihydromyricetin prevents cardiotoxicity and enhances anticancer activity induced by adriamycin.

Adriamycin, a widely used anthracycline antibiotic in multiple chemotherapy regimens, has been challenged by the cardiotoxicity leading to fatal congestive heart failure in the worst condition. The present study demonstrated that Dihydromyricetin, a natural product extracted from ampelopsis grossedentat, exerted cardioprotective effect against the injury in Adriamycin-administrated ICR mice. Dihydromyricetin decreased ALT, LDH and CKMB levels in mice serum, causing a significant reduction in the toxic death triggered by Adriamycin. The protective effects were also indicated by the alleviation of abnormal electrocardiographic changes, the abrogation of proliferation arrest and apoptotic cell death in primary myocardial cells. Further study revealed that Dihydromyricetin-rescued loss of anti-apoptosis protein ARC provoked by Adriamycin was involved in the cardioprotection. Intriguingly, the anticancer activity of Adriamycin was not compromised upon the combination with Dihydromyricetin, as demonstrated by the enhanced anticancer effect achieved by Adriamycin plus Dihydromyricetin in human leukemia U937 cells and xenograft models, in a p53-dependent manner. These results collectively promised the potential value of Dihydromyricetin as a rational cardioprotective agent of Adriamycin, by protecting myocardial cells from apoptosis, while potentiating anticancer activities of Adriamycin, thus further increasing the therapeutic window of the latter one.

miR-21 regulates N-methyl-N-nitro-N'-nitrosoguanidine-induced gastric tumorigenesis by targeting FASLG and BTG2.

MicroRNAs (miRNAs) are recently discovered regulators of gene expression and are important in the regulation of many cellular events. Evidence collected to date shows that miRNAs are altered after exposure to environmental toxicants. However, the role that miR-21 plays in the gastric tumorigenesis induced by environmental carcinogens remains largely unknown. The aim of this study was to characterize the regulatory role of miR-21 in the carcinogenic processes following exposure to the N-nitroso carcinogen N-methyl-N-nitro-N'-nitrosoguanidine (MNNG). We found a progressive dose- and time-dependent increase in miR-21 expression following treatment with MNNG. Dysregulated miR-21 affected both cell growth in GES-1 cells and the gastric tumorigenesis induced with MNNG. These data demonstrate the involvement of miR-21 in the malignant transformation and tumorigenesis activated by MNNG. We also established that the Fas ligand (FASLG) and B-cell translocation gene 2 (BTG2), regulated by miR-21, contribute to the transformation induced by MNNG in GES-1 cells. This is the first study to show that miR-21 is involved in chemical carcinogenesis in vivo and in vitro. The regulation by miR-21 of the gastric carcinogenesis induced by MNNG highlights the functional roles of miRNAs in chemical carcinogenesis, and offers a new explanation of the mechanisms underlying chemical carcinogenesis.

Autophagy blockade sensitizes the anticancer activity of CA-4 via JNK-Bcl-2 pathway.

Combretastatin A-4 (CA-4) has already entered clinical trials of solid tumors over ten years. However, the limited anticancer activity and dose-dependent toxicity restrict its clinical application. Here, we offered convincing evidence that CA-4 induced autophagy in various cancer cells, which was demonstrated by acridine orange staining of intracellular acidic vesicles, the degradation of p62, the conversion of LC3-I to LC3-II and GFP-LC3 punctate fluorescence. Interestingly, CA-4-mediated apoptotic cell death was further potentiated by pretreatment with autophagy inhibitors (3-methyladenine and bafilomycin A1) or small interfering RNAs against the autophagic genes (Atg5 and Beclin 1). The enhanced anticancer activity of CA-4 and 3-MA was further confirmed in the SGC-7901 xenograft tumor model. These findings suggested that CA-4-elicited autophagic response played a protective role that impeded the eventual cell death while autophagy inhibition was expected to improve chemotherapeutic efficacy of CA-4. Meanwhile, CA-4 treatment led to phosphorylation/activation of JNK and JNK-dependent phosphorylation of Bcl-2. Importantly, JNK inhibitor or JNK siRNA inhibited autophagy but promoted CA-4-induced apoptosis, indicating a key requirement of JNK-Bcl-2 pathway in the activation of autophagy by CA-4. We also identified that pretreatment of Bcl-2 inhibitor (ABT-737) could significantly enhance anticancer activity of CA-4 due to inhibition of autophagy. Taken together, our data suggested that the JNK-Bcl-2 pathway was considered as the critical regulator of CA-4-induced protective autophagy and a potential drug target for chemotherapeutic combination.

Altered miRNA expression profiles and miR-1a associated with urethane-induced pulmonary carcinogenesis.

MicroRNAs (miRNAs) are small RNA molecules that regulate posttranscriptional gene expression. Previous research has suggested that aberrant miRNA expression often plays a critical role in many types of cancer, including lung cancer. However, the exact miRNAs that are involved in pulmonary carcinogenesis remain unclear. We investigated the miRNA-based molecular changes that occur in urethane-induced carcinogenicity and identified specific miRNA deregulation in pulmonary carcinogenesis induced by urethane. In this study, we used a lung cancer model in which Balb/c mice were exposed to urethane via ip injection once a week for four consecutive weeks. The mice were then killed in weeks 6, 12, or 24. Two small RNA libraries were constructed with the total RNA from the lung tumor and normal adjacent lung tissues of the urethane-injected mice collected in week 24. Using Solexa sequencing, we identified a plethora of differentially expressed miRNAs and predicted nine novel miRNAs. Further analysis demonstrated the sustainable downregulation of miR-1a in the lung tissues in lung carcinogenesis induced by urethane. The levels of miR-1a were also reduced in the serum. Our findings indicate that urethane exposure alters the expression of a cluster of miRNAs. The simultaneous downregulation of miR-1a in lung tissues and serum in urethane-induced pulmonary carcinogenesis suggests that miR-1a is associated with tumorigenesis.