Compound 225# inhibits the proliferation of human colorectal cancer cells by promoting cell cycle arrest and apoptosis induction.

Colorectal cancer (CRC) ranks as the second leading cause of cancer­related death worldwide due to its aggressive nature. After surgical resection, >50% of patients with CRC require adjuvant therapy. As a result, eradicating cancer cells with medications is a promising method to treat patients with CRC. In the present study, a novel compound was synthesized, which was termed compound 225#. The inhibitory activity of compound 225# against CRC was determined by MTT assay, EdU fluorescence labeling and colony formation assay; the effects of compound 225# on the cell cycle progression and apoptosis of CRC cells were detected by flow cytometry and western blotting; and the changes in autophagic flux after the administration of compound 225# were detected using the double fluorescence fusion protein mCherry­GFP­LC3B and western blotting. The results demonstrated that compound 225# exhibited antiproliferative properties, inhibiting the proliferation and expansion of CRC cell lines in a time­ and dose­dependent manner. Furthermore, compound 225# triggered G2/M cell cycle arrest by influencing the expression of cell cycle regulators, such as CDK1, cyclin A1 and cyclin B1, which is also closely related to the activation of DNA damage pathways. The cleavage of PARP and increased protein expression levels of PUMA suggested that apoptosis was triggered after treatment with compound 225#. Moreover, the increase in LC3­II expression and stimulation of autophagic flux indicated the activation of an autophagy pathway. Notably, compound 225# induced autophagy, which was associated with endoplasmic reticulum (ER) stress. In accordance with the in vitro findings, the in vivo results demonstrated that compound 225# effectively inhibited the growth of HCT116 tumors in mice without causing any changes in their body weight. Collectively, the present results demonstrated that compound 225# not only inhibited proliferation and promoted G2/M­phase cell cycle arrest and apoptosis, but also initiated cytoprotective autophagy in CRC cells by activating ER stress pathways. Taken together, these findings provide an experimental basis for the evaluation of compound 225# as a novel potential medication for CRC treatment.

A Facile Ugi/Ullmann Cascade Reaction to Access Fused Indazolo-Quinoxaline Derivatives with Potent Anticancer Activity.

A facile methodology for the construction of a complex heterocycle indazolo-fused quinoxalinone has been developed via an Ugi four-component reaction (U-4CR) followed by an intramolecular Ullmann reaction. The expeditious process features an operationally simple approach, time efficiency, and a broad substrate scope. Biological activity was evaluated and demonstrated that compound 6e inhibits human colon cancer cell HCT116 proliferation with an IC50 of 2.1 µM, suggesting potential applications for developing a drug lead in medicinal chemistry.

Compound 275# Induces Mitochondria-Mediated Apoptosis and Autophagy Initiation in Colorectal Cancer Cells through an Accumulation of Intracellular ROS.

Colorectal cancer (CRC) is the most common intestinal malignancy, and nearly 70% of patients with this cancer develop metastatic disease. In the present study, we synthesized a novel compound, termed N-(3-(5,7-dimethylbenzo [d]oxazol-2-yl)phenyl)-5-nitrofuran-2-carboxamide (compound 275#), and found that it exhibits antiproliferative capability in suppressing the proliferation and growth of CRC cell lines. Furthermore, compound 275# triggered caspase 3-mediated intrinsic apoptosis of mitochondria and autophagy initiation. An investigation of the molecular mechanisms demonstrated that compound 275# induced intrinsic apoptosis, and autophagy initiation was largely mediated by increasing the levels of the intracellular accumulation of reactive oxygen species (ROS) in CRC cells. Taken together, these data suggest that ROS accumulation after treatment with compound 275# leads to mitochondria-mediated apoptosis and autophagy activation, highlighting the potential of compound 275# as a novel therapeutic agent for the treatment of CRC.

Pharmacological Targeting of Bcl-2 Induces Caspase 3-Mediated Cleavage of HDAC6 and Regulates the Autophagy Process in Colorectal Cancer.

Compound 6d, a spiroindoline compound, exhibits antiproliferative capability against cancer cell lines. However, the exact underlying mechanism of this compound-mediated inhibitory capability remains unclear. Here, we showed that compound 6d is an inhibitor of Bcl-2, which suppresses CRC growth by inducing caspase 3-mediated intrinsic apoptosis of mitochondria. Regarding the underlying mechanism, we identified HDAC6 as a direct substrate for caspase 3, and caspase 3 activation induced by compound 6d directly cleaves HDAC6 into two fragments. Moreover, the cleavage site was located at D1088 in the DMAD-S motif HDAC6. Apoptosis stimulated by compound 6d promoted autophagy initiation by inhibiting interaction between Bcl-2 and Beclin 1, while it led to the accumulation of ubiquitinated proteins and the reduction of autophagic flux. Collectively, our findings reveal that the Bcl-2-caspase 3-HDAC6 cascade is a crucial regulatory pathway of autophagy and identify compound 6d as a novel lead compound for disrupting the balance between apoptosis and autophagy.

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.

Discovery of fused benzimidazole-imidazole autophagic flux inhibitors for treatment of triple-negative breast cancer.

Triple-negative breast cancer (TNBC) with the absence of estrogen receptor (ER), progesterone receptor (PR) and HER2 ptotein, is the highly aggressive subtype of breast cancer that exhibits poor prognosis and high tumor recurrence. It is vital to develop effective agents regulating the core molecular pathway of TNBC. Through a medium throughput screening and iterative medicinal chemistry optimization, we identified compound 7h as an autophagic flux inhibitor, which showed potent activities against human TNBC (MDA-MB-231 and MDA-MB-468) cell lines with IC50 values of 8.3 µM, and 6.0 µM, respectively, which are comparable to the potency of 5-FU and Cisplatin, the first line therapies for TNBC. Extensive investigation of mechanisms of action indicated that 7h inhibits autophagic flux and sequential accumulation of p62, leading to DNA damage and disrepair in TNBC cells. Importantly, nuclear p62 accumulation induced by compound 7h results in the inhibition of RNF168-mediated chromatin ubiquitination and the degradation of HR-related proteins in regulating the DNA damage response (DDR) process. In in vivo studies, compound 7h completely suppressed tumor growth in the MDA-MB-231 xenograft model at a dose of 15 mg/kg/q.d. Our findings indicate that compound 7h is an autophagic flux inhibitor and induced the degradation of HR-related proteins. Compound 7h could be potentially developed as an anti-cancer therapeutics for TNBC.

Demethylzeylasteral (T-96) initiates extrinsic apoptosis against prostate cancer cells by inducing ROS-mediated ER stress and suppressing autophagic flux.

BACKGROUND: Demethylzeylasteral (T-96) is a pharmacologically active triterpenoid monomer extracted from Tripterygium wilfordii Hook F (TWHF) that has been reported to exhibit anti-neoplastic effects against several types of cancer cells. However, the potential anti-tumour effects of T-96 against human Prostate cancer (CaP) cells and the possible underlying mechanisms have not been well studied. RESULTS: In the current study, T-96 exerted significant cytotoxicity to CaP cells in vitro and induced cell cycle arrest at S-phase in a dose-dependent manner. Mechanistically, T-96 promoted the initiation of autophagy but inhibited autophagic flux by inducing ROS-mediated endoplasmic reticulum (ER) stress which subsequently activated the extrinsic apoptosis pathway in CaP cells. These findings implied that T-96-induced ER stress activated the caspase-dependent apoptosis pathway to inhibit proliferation of CaP cells. Moreover, we observed that T-96 enhances the sensitivity of CaP cells to the chemotherapeutic drug, cisplatin. CONCLUSIONS: Taken together, our data demonstrated that T-96 is a novel modulator of ER stress and autophagy, and has potential therapeutic applications against CaP in the clinic.

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.

Demethylzeylasteral (T-96) initiates extrinsic apoptosis against prostate cancer cells by inducing ROS-mediated ER stress and suppressing autophagic flux

BACKGROUND: Demethylzeylasteral (T-96) is a pharmacologically active triterpenoid monomer extracted from Tripterygium wilfordii Hook F (TWHF) that has been reported to exhibit anti-neoplastic effects against several types of cancer cells. However, the potential anti-tumour effects of T-96 against human Prostate cancer (CaP) cells and the possible underlying mechanisms have not been well studied. RESULTS: In the current study, T-96 exerted significant cytotoxicity to CaP cells in vitro and induced cell cycle arrest at S-phase in a dose-dependent manner. Mechanistically, T-96 promoted the initiation of autophagy but inhibited autophagic flux by inducing ROS-mediated endoplasmic reticulum (ER) stress which subsequently activated the extrinsic apoptosis pathway in CaP cells. These findings implied that T-96-induced ER stress activated the caspase-dependent apoptosis pathway to inhibit proliferation of CaP cells. Moreover, we observed that T-96 enhances the sensitivity of CaP cells to the chemotherapeutic drug, cisplatin. CONCLUSIONS: Taken together, our data demonstrated that T-96 is a novel modulator of ER stress and autophagy, and has potential therapeutic applications against CaP in the clinic.

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.

One-pot construction of functionalized aziridines and maleimides via a novel pseudo-Knoevenagel cascade reaction.

An Ugi, novel pseudo-Knoevenagel, ring expansion cascade reaction was discovered and utilized for the synthesis of aziridinyl succinimides in one-pot. Subsequently, densely functionalized aziridines and maleimides have been designed and synthesized through similar cascade reactions. The target compounds were prepared by means of a mild reaction and a simple operation procedure, which could be applicable to a broad scope of starting materials. This series of novel cascade reactions generates opportunities for the tailored synthesis of a wide range of biologically active scaffolds through tuneable Ugi inputs. Discovery of compound 8i with comparable potency to sorafenib in liver cancer cell lines could provide a new avenue for liver cancer drug discovery.

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.

Structural Based Screening of Antiandrogen Targeting Activation Function-2 Binding Site.

Androgen receptor (AR) plays a critical role in the development and progression of prostate cancer (PCa). Current antiandrogen therapies induce resistant mutations at the hormone binding pocket (HBP) that convert the activity of these agents from antagonist to agonist. Thus, there is a high unmet medical need for the development of novel antiandrogens which circumvent mutation-based resistance. Herein, through the analysis of AR structures with ligands binding to the activation function-2 (AF2) site, we built a combined pharmacophore model. In silico screening and the subsequent biological evaluation lead to the discovery of the novel lead compound IMB-A6 that binds to the AF2 site, which inhibits the activity of either wild-type (WT) or resistance mutated ARs. Our work demonstrates structure-based drug design is an efficient strategy to discover new antiandrogens, and provides a new class of small molecular antiandrogens for the development of novel treatment agents against PCa.

Benzimidazoisoquinoline derivatives inhibit glioblastoma cell proliferation through down-regulating Raf/MEK/ERK and PI3K/AKT pathways.

BACKGROUND: Recent studies showed that benzimidazoleisoquinolinone derivatives exhibit anticancer activity against human cancer cell lines. The aim of this study is to evaluate the anti-tumor effects and mechanisms of benzimidazoleisoquinolinones in isocitrate dehydrogenase-wildtype subtype of human glioblastoma (GBM) cells. METHODS: Human U87 and LN229 cell lines were used to perform the experiments. MTT was applied to screen the effective small molecular inhibitors suppressing growth of GBM cells. Colony formation and BrdU staining assays were performed to assess the inhibition effect of compound-1H on the proliferation of GBM cells. The cell cycle and apoptosis were measured by flow cytometry and western blot to analyze the changes of the relative protein expressions and their signal pathways. RESULTS: Compound-1H could suppress GBM cells in a time- and dose-dependent manner. Treatment of compound-1H could arrest cell cycle in S phase through up-regulating P21 and P53, and down-regulating cyclin A and E in a dose-dependent manner. Compound-1H also induced mitochondrial-dependent apoptosis by increasing Bax, cleaved caspase-3, cleaved caspase-9 and poly ADP-ribose polymerase expression, and decreasing Bcl-2 expression. Moreover, phosphorylated (p)-AKT and p-ERK levels relating to cell proliferation were dramatically decreased in U87 and LN229 cells. CONCLUSIONS: Our results suggest that it is the first time to report the compound-1H with benzimidazoleisoquinolinone core playing antitumor activity in human glioblastoma cells by inhibiting Raf/MEK/ERK and PI3K/AKT signaling pathways, and it could be as a lead compound for the further development of targeted glioblastoma cancer therapy.

Facile construction of fused benzimidazole-isoquinolinones that induce cell-cycle arrest and apoptosis in colorectal cancer cells.

Colorectal cancer (CRC) is one of the most frequent, malignant gastrointestinal tumors, and strategies and effectiveness of current therapy are limited. A series of benzimidazole-isoquinolinone derivatives (BIDs) was synthesized and screened to identify novel scaffolds for CRC. Of the compounds evaluated, 7g exhibited the most promising anti-cancer properties. Employing two CRC cell lines, SW620 and HT29, 7g was found to suppress growth and proliferation of the cell lines at a concentration of ∼20 µM. Treatment followed an increase in G2/M cell cycle arrest, which was attributed to cyclin B1 and cyclin-dependent kinase 1 (CDK1) signaling deficiencies with simultaneous enhancement in p21 and p53 activity. In addition, mitochondrial-mediated apoptosis was induced in CRC cells. Interestingly, 7g decreased phosphorylated AKT, mTOR and 4E-BP1 levels, while promoting the expression/stability of PTEN. Since PTEN controls input into the PI3K/AKT/mTOR pathway, antiproliferative effects can be attributed to PTEN-mediated tumor suppression. Collectively, these results suggest that BIDs exert antitumor activity in CRC by impairing PI3K/AKT/mTOR signaling. Against a small kinase panel, 7g exhibited low affinity at 5 µM suggesting anticancer properties likely stem through a non-kinase mechanism. Because of the novelty of BIDs, the structure can serve as a lead scaffold to design new CRC therapies.

Functionalized Spiroindolines with Anticancer Activity through a Metal-Free Post-Ugi Diastereoselective One-Pot Cascade Reaction.

A post-Ugi diastereoselective one-pot cascade reaction requiring no metal catalyst was developed. The reaction scope was wide with mild conditions and good yields. A collection of spiroindolines was prepared by the protocol and screening tests in several difficult-to-inhibit cancer cell lines were conducted. The relationship of structure and anticancer activities was promising and in the Huh7 cell lines compound 16 j is more potent than Vinbalstine. The cyclization design strategy could be applicable to other multicomponent reactions (MCRs) for synthesizing bioactive and drug-like heterocycles.

[MicroRNA regulates animal adipocyte differentiation].

Adipose tissues play a critical role in the regulation of energy metabolism and homeostasis, and is also an important endocrine organ. Adipocyte differentiation is a complicated physiological process during which mesenchymal stem cells differentiate into adipocytes. This process is synergistically regulated by a large number of transcription factors, hormones and signaling pathway molecules. As a class of endogenous non-coding RNA (ncRNA), microRNAs (miRNAs) regulate gene expression mainly through post-transcriptional translational repression. In recent years, numerous studies have demonstrated that miRNA could have an impact on adipocyte differentiation and adipogenesis by modulating the expression levels of several adipogenic transcription factors and key signaling molecules. In this review, we summarize the mechanism of miRNA in regulating the differentiation of white/brown/beige adipocytes and the relevant signaling pathways and key factors, in the hope of providing theoretical guidance and new thoughts for treating obesity and other metabolic diseases.