Pyrrolyldihydropyrazino[1,2-a]indoletrione Analogue Microtubule Inhibitor Induces Cell-Cycle Arrest and Apoptosis in Colorectal Cancer Cells.

In this study, 2-benzyl-10a-(1H-pyrrol-2-yl)-2,3-dihydropyrazino[1,2-a]indole-1,4,10(10aH)-trione (DHPITO), a previously identified inhibitor against hepatocellular carcinoma cells, is shown to exert its cytotoxic effects by suppressing the proliferation and growth of CRC cells. An investigation of its molecular mechanism confirmed that the cytotoxic activity of DHPITO is mediated through the targeting of microtubules with the promotion of subsequent microtubule polymerisation. With its microtubule-stabilising ability, DHPITO also consistently arrested the cell cycle of the CRC cells at the G2/M phase by promoting the phosphorylation of histone 3 and the accumulation of EB1 at the cell equator, reduced the levels of CRC cell migration and invasion, and induced cellular apoptosis. Furthermore, the compound could suppress both tumour size and tumour weight in a CRC xenograft model without any obvious side effects. Taken together, the findings of the present study reveal the antiproliferative and antitumour mechanisms through which DHPITO exerts its activity, indicating its potential as a putative chemotherapeutic agent and lead compound with a novel structure.

One-pot synthesis of substituted pyrrole-imidazole derivatives with anticancer activity.

A facile and efficient method to synthesize pyrrole-imidazole was developed via a post-Ugi cascade reaction followed by one purification procedure. Synthesized pyrrole-imidazole was collected by performing a mild reaction and a simple procedure, which could be applicable to a broad scope of functionalized anilines. The screening results demonstrated that compound 7e exhibited a high potency of anticancer activity in human pancreatic cancer cell lines PANC and ASPC-1. Our work shed light on the potential of post-Ugi cascade reaction in combinatorial and medicinal chemistry.

A Derivate of Benzimidazole-Isoquinolinone Induces SKP2 Transcriptional Inhibition to Exert Anti-Tumor Activity in Glioblastoma Cells.

We have previously shown that compound-7g inhibits colorectal cancer cell proliferation and survival by inducing cell cycle arrest and PI3K/AKT/mTOR pathway blockage. However, whether it has the ability to exert antitumor activity in other cancer cells and what is the exact molecular mechanism for its antiproliferation effect remained to be determined. In the present study, compound-7g exhibited strong activity in suppressing proliferation and growth of glioblastoma cells. The inhibitor selectively downregulated F-box protein SKP2 expression and upregulated cell cycle inhibitor p27, and then resulted in G1 cell cycle arrest. Mechanism analysis revealed that compound-7g also provokes the down-regulation of E2F-1, which acts as a transcriptional factor of SKP2. Further results indicated that compound-7g induced an increase of LC3B-II and p62, which causes a suppression of fusion between autophagosome and lysosome. Moreover, compound-7g mediated autophagic flux blockage promoted accumulation of ubiquitinated proteins and then led to endoplasmic reticulum stress. Our study thus demonstrated that pharmacological inactivation of E2F-1-SKP2-p27 axis is a promising target for restricting cancer progression.

DMAPT­D6 induces death­receptor­mediated apoptosis to inhibit glioblastoma cell oncogenesis via induction of DNA damage through accumulation of intracellular ROS.

Glioblastoma (GBM) is an aggressive malignancy with a high rate of tumor recurrence after treatment with conventional therapies. Parthenolide (PTL), a sesquiterpene lactone extracted from the herb Tanacetum parthenium or feverfew, possesses anticancer properties against a wide variety of solid tumors. In the present study, a series of PTL derivatives were synthesized and screened. An inhibitor, dimethylaminoparthenolide (DMAPT)­D6, a derivative of the PTL prodrug DMAPT in which the hydrogen of the dimethylamino group is substituted for the isotope deuterium, induced significant cytotoxicity in GBM cells in vitro and induced cell cycle arrest at the S­phase in a dose­dependent manner. Furthermore, mechanistic investigation indicated that through increasing the levels of intracellular accumulation of reactive oxygen species (ROS), DMAPT­D6 triggered DNA damage and finally death receptor­mediated extrinsic apoptosis in GBM cells, suggesting that DNA damage induced by DMAPT­D6 initiated caspase­dependent apoptosis to remove damaged GBM cells. Taken together, these data suggested that ROS accumulation following treatment with DMAPT­D6 results in DNA damage, and thus, death­receptor­mediated apoptosis, highlighting the potential of DMAPT­D6 as a novel therapeutic agent for the treatment of GBM.

A Novel Imidazopyridine Derivative Exhibits Anticancer Activity in Breast Cancer by Inhibiting Wnt/ß­catenin Signaling.

BACKGROUND: Breast cancer exhibits poor prognosis and high relapse rates following chemotherapy therapeutics. Thus, this study aims to develop effective novel agents regulating the core molecular pathway of breast cancer such as Wnt/ß-catenin signaling. METHODS: The present study screened a novel inhibitor, called "C188", using MTT assay. The molecular formula of C188 is C21H15FN4O3 and the molecular weight is 390. Flow cytometry and Western blotting were employed to assess cell cycle arrest after treatment with C188. Wound-healing and transwell assays were applied to measure the cell migration and invasion viability. The regulatory effects of C188 on Wnt/ß­catenin signaling and localization of ß­catenin in the nucleus were investigated by Western blotting and immunofluorescence. RESULTS: We found that C188 significantly suppressed proliferation and growth in a dose- and time-dependent manner in breast cancer cells, but not in normal breast cells. The inhibitory effect was caused by cell cycle arrest at the G1-phase which is induced by C188 treatment. Additionally, C188 dramatically inhibited cell migration of breast cancer cells in a dose-dependent manner. The migration inhibition was attributed to the suppression of Wnt/ß­catenin signaling and localization of ß­catenin in the nucleus mediated by regulating phosphorylation of ß­catenin and its subsequent stability. Furthermore, the target genes, including Axin 2, c-JUN, and c-Myc, were downregulated due to the decrease of ß­catenin in the nucleus after exposure to C188. CONCLUSION: C188 treatment resulted in the downregulation of cyclin D which led to cell cycle arrest at the G1 phase, and the inhibition of cell migration, indicating that C188 may be an effective novel therapeutic candidate as a potential treatment for human breast cancer.

[Effects of Choukroun's platelet-rich fibrin on human gingival fibroblasts proliferation, migration and type I collagen secretion].

OBJECTIVE: To investigate the effect of platelet-rich fibrin (PRF) on human gingival fibroblasts (HGF) biological behavior such as proliferation, migration and collagen-I expression. METHODS: Human healthy gingival tissues were cultured according to the explant technique to obtain primary cultures. PRF was prepared by means of Choukroun's. HGF were co-cultured with PRF membrane originating from the same donor as the explants, divided into three groups, PRF1 group, PRF2 group and blank control group. Methyl thiazolyl tetrazolium (MTT) assay was used for cytotoxicity and cell proliferation study, and enzyme-linked immunosorbent assay (ELISA) for collagen-I (COL-I) secretion study at the 1st, 3rd, 5th day respectively. Eluates from PRF membrane was prepared, and divided into three groups, PRF1 group, PRF2 group and blank control group. Transwell chamber was utilized to determine the effect of PRF membrane eluate on cell migration. RESULTS: The A values of HGF in culture of the PRF1 (0.615 ± 0.036, 0.686 ± 0.006, 0.693 ± 0.004) and PRF2 groups (0.653 ± 0.023, 0.766 ± 0.034, 0.775 ± 0.053) were significantly higher than those of the control cultures (0.514 ± 0.020, 0.544 ± 0.006, 0.545 ± 0.009) (P < 0.01), but the difference between PRF1 and PRF2 group was not significant (P > 0.05). In each group at different time points, the HGF proliferation effect was significantly enhanced with time (P < 0.01). Cell migration test showed that the migration numbers of HGF in PRF1 and PRF2 groups (85.67 ± 2.94, 85.83 ± 1.47) were significantly higher than those of the control group (54.17 ± 2.48) (P < 0.01), but the difference between the two experimental groups was not significant (P > 0.05). COL-I secretion test exhibited that the A values of COL-I in PRF1 (0.184 ± 0.004, 0.200 ± 0.004, 0.204 ± 0.009) and PRF2 group (0.213 ± 0.008, 0.226 ± 0.005, 0.229 ± 0.006) were significantly higher than the A values of the control group (0.174 ± 0.002, 0.184 ± 0.002, 0.186 ± 0.003) (P < 0.01), but the difference between the two experimental groups was not significant (P > 0.05). In each group, the secretion level of COL-I increased significantly with time (P < 0.01). CONCLUSIONS: PRF could exert a positive effect on HGF biological behaviour and had clinical application potential in the treatment of gingival recession and in the periodontal tissue engineering when combined with seed cell HGF.

[Isolation and characterization of a DRE-binding transcription factor from Yinxin poplar (Populus alba x P. alba var. pyramidalis)].

Dehydration-Responsive Element Binding ( DREB) transcription factors, specifically binding with dehydration reponsive element (DRE), activate a variety of stress-responsive genes in plants under abiotic stresses (dehydration, high salt and low temperature). Using PCR and homologous EST search, we isolated a DREB-like gene from Yinxin poplar (Populus alba x P. alba var. pyramidalis) named PaDREB2. Yeast One-hybrid experiment demonstrated that PaDREB2 protein could function as a DREB transcription factor activating target gene expression by specifically binding to DRE cis-element. To study the expression pattern of PaDREB2, RT-PCR was carried out. And the results showed that PaDREB2 is induced by low temperature, drought and high salt.