BET inhibitor bromosporine enhances 5-FU effect in colorectal cancer cells

Treatment of colorectal cancer (CRC) remains a challenge because of the lack of effective early treatment strategies and high incidence of relapse. 5-Fluorouracil (5-FU) is a typical CRC treatment. Bromosporine is an innovative bromodomain and extraterminal domain (BET) inhibitor. We investigated if CRC could be targeted by the combination of 5-FU and bromosporine in a synergistic manner in vivo and in vitro. Our findings shown that the combination treatment inhibits cell viability, formation of colonies, increased apoptosis and cell cycle arrest at G0-G1. In addition, the expression level of BRD4 was high in HCT116 cells exposed to 5-FU that showed lower apoptosis against the parental cells. Moreover, the 5-FU-resistance was reversed significantly by BRD4 knockdown or inhibition. The drug combination showed increased activity against tumor than individual drug exposure in the xenograft model. In conclusion, this work serves as a basic clinical evaluation of 5-FU and bromosporine as an effective therapeutic approach for CRC.     

Discovery of a novel DNA binding agent via design and synthesis of new thiazole hybrids and fused 1,2,4-triazines as potential antitumor agents: Computational,spectrometric and in silico studies

New series of furan–thiazole hybrids (3a-f), thiazolo[2,3-c]-1,2,4-triazines (4a-f), their bioisosteres 1,3,4-thiadiazolo[2,3-c]-1,2,4-triazines (8a-d) and 1,2,4-triazino[4,3-b]-1,2,4-triazines (13a-e) were designed, synthesized and evaluated for their in vitro antitumor activities at the National Cancer Institute (NCI, USA). Among the synthesized compounds, 3d was found to exhibit promising broad spectrum antitumor activity (GI₅₀ MG-MID = 14.22 µM) in a five-dose assay against the full panel NCI-cancer cell lines. 3d displayed higher antitumor activity against most tested cancer cell lines than 5-FU as reference. COMPARE analysis and molecular electrostatic potential computational study revealed that 3d probably exerts its antitumor properties through DNA binding similar to Clomesone. Further DNA binding studies using fluorescent terbium (Tb⁺³) probe revealed increased fluroresence of DNA-3d-Tb⁺³ mixture due to damage of the double-stranded DNA. Also, UV–vis absorption study was conducted which showed hyperchromic shift in DNA absorption confirming 3d-induced DNA damage. The assessed potency of 3d-induced DNA damage of calf thymus DNA showed a concentration as low as 2.04 ng/mL for a detectable DNA damage. Moreover, in silico calculation of physicochemical properties and druglikeness were in compliance to Lipinski’s rule.     

Propolis Enhances 5-Fluorouracil Mediated Antitumor Efficacy and Reduces Side Effects in Colorectal Cancer: An in Vitro and in Vivo Study

In this study, we investigated the combined treatment of 5-fluorouracil (5-FU) and Anatolian propolis extract (PE) on colorectal cancer (CRC)using in vitro and in vivo studies. We exposed luciferase-transfected (Lovo-Luc CRC) cells and healthy colon cells (CCD-18Co) to varying concentrations of 5-FU and PE to assess their genotoxic, apoptotic, and cytotoxic effects, as well as their intracellular reactive oxygen species (iROS) levels. We also developed a xenograft model in nude mice and evaluated the anti-tumor effects of PE and 5-FU using various methods. Our findings showed that the combination of PE and 5-FU had selectivity against cancer cells, particularly at higher doses, and enhanced the anti-tumor effectiveness of 5-FU against colon CRC. The results suggest that PE can reduce side effects and increase the effectiveness of 5-FU through iROS generation in a dose-dependent manner.     

Low curcumin concentration enhances the anticancer effect of 5-fluorouracil against colorectal cancer

BackgroundColon cancer treatments include surgery, radiotherapy, and chemotherapy. Chemotherapy using 5-fluorouracil (5-FU) has been widely applied to treat colorectal cancer (CRC). However, it is important to explore the use of chemotherapy drugs in combination with other agents to decrease severe adverse effects.PurposeThis study aimed to investigate the effects of curcumin in combination with 5-FU on the proliferation, migration, and apoptosis of CRC SW620 cell line both in vitro and in vivo.MethodsFlow cytometry was used to study the effect of curcumin on chemotherapy-induced apoptosis in CRC cells. The mechanism of curcumin's enhanced antitumor effect in vivo was investigated using gene knockdown, TUNEL, western blot, qRT-PCR and immunohistochemistry.ResultsThe results showed a synergistic effect of the two compounds on CRC cells. Considerable reduction in the proliferation and migration of SW620 cells was observed in the combination treatment group. Significantly increased apoptosis rate extended the survival of immunodeficient mice in the combination group as compared to that of the 5-FU group (p < 0.05). The results showed that curcumin significantly inhibited pERK signaling and downregulated L1 expression in SW620 cells.ConclusionsWe conclude that curcumin promotes chemosensitivity of CRC cells to 5-FU by downregulating L1 expression. Our findings provide experimental evidence for the synergism between curcumin and 5-FU, which can be utilized in clinical applications for reducing the toxicity and adverse effects of 5-FU.     

Circ-ERBB2 knockdown sensitized colorectal cancer cells to 5-FU via miR-181a-5p/PTEN/Akt pathway

Colorectal cancer (CRC) is the fourth most deadly cancer worldwide, drug resistance impedes treatment of CRC. It is still urgent to find new molecular targets to improve the sensitivity of chemotherapeutic drugs. In this study, circ-ERBB2 was upregulated in CRC cells. Upregulation of circ-ERBB2 promoted CRC cells proliferation and clone formation, but inhibited apoptosis. We identified miR-181a-5p as circ-ERBB2's target. The effect of miR-181a-5p on CRC cells was contrary to circ-ERBB2, miR-181a-5p downregulation abolished the function of circ-ERBB2 silencing in CRC cells. In addition, phosphatase and tensin homolog (PTEN) was verified as miR-181a-5p's downstream target, circ-ERBB2 activates the Akt pathway and inhibits cell apoptosis through modulating miR-181a-5p/PTEN. Circ-ERBB2 silencing significantly reduced CRC cell resistance to 5-FU. miR-181a-5p downregulation abolished the role of circ-ERBB2 knockdown in CRC cell resistance to 5-FU. In conclusion, upregulation of circ-ERBB2 promoted the malignancy of CRC and reduced CRC cell resistance to 5-FU. Besides, additional mechanism study provided a novel regulatory pathways that circ-ERBB2 knockdown promoted CRC cell sensitivity to 5-FU by regulating miR-181a-5p/PTEN/Akt pathway. This research indicated that circ-ERBB2 may be a valuable biomarker for the diagnosis and treatment of CRC.     

Novel [1,2,4]triazolo[1,5-a]pyrimidine derivatives as potent antitubulin agents: Design,multicomponent synthesis and antiproliferative activities

As restricted CA-4 analogues, a novel series of [1,2,4]triazolo[1,5-a]pyrimidines possessing 3,4,5-trimethoxylphenyl groups has been achieved successfully via an efficient one-pot three-component reaction of 3-(3,4,5-trimethoxyphenyl)-1H-1,2,4-triazol-5-amine, 1,3-dicarbonyl compounds and aldehydes. Initial biological evaluation demonstrated some of target compounds displayed potent antitumor activity in vitro against three cancer cell lines. Among them, the most highly active analogue 26 inhibited the growth of HeLa, and A549 cell lines with IC₅₀ values at 0.75, and 1.02 μM, respectively, indicating excellent selectivity over non-tumoural cell line HEK-293 (IC₅₀ = 29.94 μM) which suggested that the target compounds might possess a high safety index. Moreover, cell cycle analysis illustrated that the analogue 26 significantly induced HeLa cells arrest in G2/M phase, meanwhile the compound could dramatically affect cell morphology and microtubule networks. In addition, compound 28 exhibited potent anti-tubulin activity with IC₅₀ values of 9.90 μM, and molecular docking studies revealed the analogue occupied the colchicine-binding site of tubulin. These observations suggest that [1,2,4]triazolo[1,5-a]pyrimidines represent a new class of tubulin polymerization inhibitors and well worth further investigation aiming to generate potential anticancer agents.     

Curcumin Chemosensitizes 5-Fluorouracil Resistant MMR-Deficient Human Colon Cancer Cells in High Density Cultures

Objective

Treatment of colorectal cancer (CRC) remains a clinical challenge, as more than 15% of patients are resistant to 5-Fluorouracil (5-FU)-based chemotherapeutic regimens, and tumor recurrence rates can be as high as 50–60%. Cancer stem cells (CSC) are capable of surviving conventional chemotherapies that permits regeneration of original tumors. Therefore, we investigated the effectiveness of 5-FU and plant polyphenol (curcumin) in context of DNA mismatch repair (MMR) status and CSC activity in 3D cultures of CRC cells.

Methods

High density 3D cultures of CRC cell lines HCT116, HCT116+ch3 (complemented with chromosome 3) and their corresponding isogenic 5-FU-chemo-resistant derivative clones (HCT116R, HCT116+ch3R) were treated with 5-FU either without or with curcumin in time- and dose-dependent assays.

Results

Pre-treatment with curcumin significantly enhanced the effect of 5-FU on HCT116R and HCR116+ch3R cells, in contrast to 5-FU alone as evidenced by increased disintegration of colonospheres, enhanced apoptosis and by inhibiting their growth. Curcumin and/or 5-FU strongly affected MMR-deficient CRC cells in high density cultures, however MMR-proficient CRC cells were more sensitive. These effects of curcumin in enhancing chemosensitivity to 5-FU were further supported by its ability to effectively suppress CSC pools as evidenced by decreased number of CSC marker positive cells, highlighting the suitability of this 3D culture model for evaluating CSC marker expression in a close to vivo setting.

Conclusion

Our results illustrate novel and previously unrecognized effects of curcumin in enhancing chemosensitization to 5-FU-based chemotherapy on DNA MMR-deficient and their chemo-resistant counterparts by targeting the CSC sub-population. (246 words in abstract).     

Combined 5-FU and ChoKα Inhibitors as a New Alternative Therapy of Colorectal Cancer: Evidence in Human Tumor-Derived Cell Lines and Mouse Xenografts

Background

Colorectal cancer (CRC) is the third major cause of cancer related deaths in the world. 5-fluorouracil (5-FU) is widely used for the treatment of colorectal cancer but as a single-agent renders low response rates. Choline kinase alpha (ChoKα), an enzyme that plays a role in cell proliferation and transformation, has been reported overexpressed in many different tumors, including colorectal tumors. ChoKα inhibitors have recently entered clinical trials as a novel antitumor strategy.

Methodology/Principal Findings

ChoKα specific inhibitors, MN58b and TCD-717, have demonstrated a potent antitumoral activity both in vitro and in vivo against several tumor-derived cell line xenografts including CRC-derived cell lines. The effect of ChoKα inhibitors in combination with 5-FU as a new alternative for the treatment of colon tumors has been investigated both in vitro in CRC-tumour derived cell lines, and in vivo in mouse xenografts models. The effects on thymidilate synthase (TS) and thymidine kinase (TK1) levels, two enzymes known to play an essential role in the mechanism of action of 5-FU, were analyzed by western blotting and quantitative PCR analysis. The combination of 5-FU with ChoKα inhibitors resulted in a synergistic effect in vitro in three different human colon cancer cell lines, and in vivo against human colon xenografts in nude mice. ChoKα inhibitors modulate the expression levels of TS and TK1 through inhibition of E2F production, providing a rational for its mechanism of action.

Conclusion/Significance

Our data suggest that both drugs in combination display a synergistic antitumoral effect due to ChoKα inhibitors-driven modulation of the metabolization of 5-FU. The clinical relevance of these findings is strongly supported since TCD-717 has recently entered Phase I clinical trials against solid tumors.     

ZNF746 plays cardinal roles on colorectal cancer (CRC) cell invasion and migration and regulates mitochondrial dynamics and morphological changes of CRC cells—Role of combined melatonin and 5-FU regimen

The underlying mechanism of colorectal cells developing into cancer cells has been extensively investigated, yet is still not fully delineated, resulting in the treatment of advanced colorectal cancer (CRC) remains regrettably an unmet need. Zinc Finger Protein 746/Parkin-interacting substrate (ZNF746/PARIS) has previously been identified to play a fundamental role on bladder cancer cell proliferation and metastasis that were effectively inhibited by melatonin (Mel). In this study, we utilized ex vivo/in vivo studies to verify whether the ZNF746 signaling was also crucial in CRC growth/invasion/migration. Tissue-bank specimens showed that the protein expression of ZNF746 was significantly increased in CRC than that of healthy colorectal tissues (p < 0.001). Additionally, in vitro study demonstrated that excessive expression of ZNF746 significantly inhibited mitochondrial activity via (1) interfering with the dynamic balance of mitochondrial fusion/fission and (2) inhibiting the protein expression of MFN1/MFN2/PGC1a (all p < 0.001). Furthermore, we identified that inhibition of ZNF746 protein expression significantly reduced the resistance of CRC cell lines to the anticancer drug of 5-FU (p < 0.001), whereas overexpression of ZNF746 significantly augmented resistance of CRC cells to 5-FU (all p < 0.001). Finally, using the cell culture method, we found that combined Mel and 5-FU was superior to merely one on promoting the CRC cell apoptosis (p < 0.001). Our results confirmed that ZNF746 signaling played a cardinal role of CRC cell proliferation/survival and combined Mel and 5-FU treatment attenuated the resistance of CRC cells to the drug mainly through suppressing this signaling.     

New copper(II), nickel(II) and zinc(II) complexes with 1,2,4-triazolo[1,5-a]pyrimidines and the chelating ligand 1,3-propanediamine: An unexpected coordination behavior for the 7-amine-derivative

Five new metal complexes with the metal ions Cu(II), Ni(II) and Zn(II) and containing 1,2,4-triazolo[1,5-a]pyrimidine derivatives and 1,3-propanediamine (tn) are described. The structural morphology of these coordination compounds depends on the triazolopyrimidine derivative used, being mononuclear for 5,7-dimethyl-1,2,4-triazolo[1,5-a]pyrimidine (dmtp) and 5-methyl-1,2,4-triazolo[1,5-a]pyrimidin-7(4H)-one (HmtpO), and 1D-polymeric for 7-amine-1,2,4-triazolo[1,5-a]pyrimidine (7atp). In the 7atp case, this ligand does not coordinate through N3 atom, as expected, but through N1, N4 and N71 in a bridging fashion. This unexpected coordination mode seems to be induced by the stability of the polynuclear metal complex in presence of tn ligand. All isolated metal complexes have been characterized by single-crystal X-ray diffraction, IR and UV-Vis spectroscopies, and EPR measurements. Moreover, luminescence measurements have been carried out for 7atp ligand and its polynuclear complex with Zn(II).     

lncRNA XIST-miR137-ATG5调节细胞自噬功能在肠癌细胞5-氟胞嘧啶耐药性中的作用

摘要 目的：本文旨在研究长链非编码RNA XIST-miR137-ATG5的相互作用,同时探讨其调节细胞自噬功能与肠癌细胞5-氟胞嘧啶敏感性的关系。方法：实时聚合酶链反应(real time PCR)检测XIST与miR-137在肠癌细胞中的表达;采用脂质体转染法将si-XIST,miR-137转染入肠癌SW480及HCT116细胞中。采用CCK-8检测瞬时转染si-XIST对肠癌细胞增殖及5-FU敏感性的影响;并利用双荧光素酶报告实验检测miR-137与XIST, miR-137与ATG5相互关系。Western blot方法检测XIST- miR137- ATG5对细胞自噬的影响。结果：与正常结肠细胞FHC比较, XIST在结肠癌细胞系明显高表达,miR-137在结肠癌细胞系明显低表达。与阴性对照组比较,转染si-XIST后,SW480及HCT116细胞增殖能力明显受到抑制,对F-5U的敏感性增强,且抑制自噬蛋白Beclin-1及LC3II/LC3 I的表达。miR-137可与XIST,ATG5 3''UTR结合,抑制XIST和ATG5的表达及功能。在结肠癌SW480细胞中共转染miR-137 inhibitor或过表达ATG5可逆转XIST沉默引起的5-FU耐药,同时可逆转因XIST沉默引起的自噬蛋白表达的抑制。结论：LncRNA XIST或可通过调控mir137-ATG促进结直肠癌细胞SW480自噬从而提高其对5-FU的耐药,针对其这一机制,可为将来针对结肠癌的靶向治疗提供一定的实验基础。     

Synthesis of carbon-11-labeled 4-(phenylamino)-pyrrolo[2,1-f][1,2,4]triazine derivatives as new potential PET tracers for imaging of p38α mitogen-activated protein kinase

The reference standards methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate (10b) and corresponding precursors 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11a), methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylic acid (11b) were synthesized from methyl crotonate and 3-amino-4-methylbenzoic acid in multiple steps with moderate to excellent yields. The target tracer [¹¹C]methyl 4-(2-methyl-5-(methoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([¹¹C]10a) and [¹¹C]methyl 4-(2-methyl-5-(ethoxycarbamoyl)phenylamino)-5-methylpyrrolo[2,1-f][1,2,4]triazine-6-carboxylate ([¹¹C]10b) were prepared from their corresponding precursors with [¹¹C]CH₃OTf under basic condition through O-[¹¹C]methylation and isolated by a simplified solid-phase extraction (SPE) method in 50–60% radiochemical yields at end of bombardment (EOB) with 185–555 GBq/μmol specific activity at end of synthesis (EOS).     

miR-129 promotes apoptosis and enhances chemosensitivity to 5-fluorouracil in colorectal cancer

Resistance to fluoropyrimidine-based chemotherapy is the major reason for the failure of advanced colorectal cancer (CRC) treatment. The lack of ability of tumor cells to undergo apoptosis after genotoxic stress is the key contributor to this intrinsic mechanism. Mounting evidence has demonstrated that non-coding microRNAs (miRNAs) are crucial regulators of gene expression, in particular, under acute genotoxic stress. However, there is still limited knowledge about the role of miRNAs in apoptosis. In this study, we discovered a novel mechanism mediated by microRNA-129 (miR-129) to trigger apoptosis by suppressing a key anti-apoptotic protein, B-cell lymphoma 2 (BCL2). Ectopic expression of miR-129 promoted apoptosis, inhibited cell proliferation and caused cell-cycle arrest in CRC cells. The intrinsic apoptotic pathway triggered by miR-129 was activated by cleavage of caspase-9 and caspase-3. The expression of miR-129 was significantly downregulated in CRC tissue specimens compared with the paired normal control samples. More importantly, we demonstrated that miR-129 enhanced the cytotoxic effect of 5-fluorouracil both in vitro and in vivo. These results suggest that miR-129 has a unique potential as a tumor suppressor and a novel candidate for developing miR-129-based therapeutic strategies in CRC.     

Discovery of novel [1,2,4]triazolo[4,3-a]quinoxaline aminophenyl derivatives as BET inhibitors for cancer treatment

Bromodomain and extra-terminal (BET) proteins, a class of epigenetic reader domains has emerged as a promising new target class for small molecule drug discovery for the treatment of cancer, inflammatory, and autoimmune diseases. Starting from in silico screening campaign, herein we report the discovery of novel BET inhibitors based on [1,2,4]triazolo[4,3-a]quinoxaline scaffold and their biological evaluation. The hit compound was optimized using the medicinal chemistry approach to the lead compound with excellent inhibitory activities against BRD4 in the binding assay. The substantial antiproliferative activities in human cancer cell lines, promising drug-like properties, and the selectivity for the BET family make the lead compound (13) as a novel BRD4 inhibitor motif for anti-cancer drug discovery.     

PB-10, a thiazolo[4,5-d] pyrimidine derivative,targets p21-activated kinase 4 in human colorectal cancer cells

Targeting p21-activated kinase 4 (PAK4) is a potential therapeutic strategy against human colorectal cancer (CRC). In this study, we synthesized a series of novel thiazolo[4,5-d]pyrimidine derivatives (PB-1–12) and identified PB-10 (PAK4 IC₅₀ = 15.12 μM) as a potential and potent PAK4 inhibitor. Our results showed that PB-10 significantly suppressed the proliferation and colony formation of human CRC cells. PB-10 also arrested HCT-116 CRC cells at sub G0/G1 phase while promoting the expression of proapoptotic proteins. In addition, PB-10 inhibited migration, invasion, and adhesion as well as the PAK4 downstream signaling pathway in HCT-116 cells. Molecular docking analysis showed possible binding modes between PB-10 and PAK4. Our study provides a novel compound that may block the PAK4 signaling in CRC cells.     

Site selectivity in reactions of hydrazonoyl halides with heterocycles containing amino and thione groups leading to fused heterocycles of potential antimicrobial activity

Reaction of hydrazonoyl halides with 6-(benzylidenamino)-2-thioxo-2,3-dihydro-1H-pyrimidin-4-one and 2,3-diaminoquinazolin-4-one site-selectively afforded 3-substituted-7-(benzylidenamino)-1-phenyl-[1,2,4]triazolo[4,3-a]-pyrimidin-5(1H)-ones, [1,2,4,5]tetrazino[6,1-b]quinazolin-6(4H)-one, and 3-methyl-2-(4-substituted-phenylhydrazo)-[1,2,4]triazino[3,2-b]quinazolin-10-ones in good yields. The structures of the newly synthesized compounds were elucidated by chemical evidence and their IR, ¹H, ¹³C NMR, and MS spectra. Furthermore, some of the products were screened against different strains of bacteria and fungi.     

Pyrazolo[4,3-e][1,2,4]triazine sulfonamides as carbonic anhydrase inhibitors with antitumor activity

A series of sildenafil analogues and aniline substituted pyrazolo[4,3-e][1,2,4]triazine sulfonamides were prepared and evaluated as carbonic anhydrase (CA, EC 4.2.1.1) inhibitors and for their anticancer activity against two human breast cancer cell lines (MCF-7, MDA-MB-231). The new compounds were ineffective as CA I inhibitors, poorly inhibited CA II, but were more effective against the tumor-associated isoforms CA IX and XII, with some compounds acting as low nanomolar inhibitors. Evaluation of the cytotoxicity by using an MTT assay, the inhibition of [³H]thymidine incorporation into DNA as well as collagen synthesis inhibition, demonstrated that these sulfonamides exhibit cytotoxic effects on breast cancer cell lines ex vivo.