Discovery of novel nucleoside derivatives as selective lysine acetyltransferase p300 inhibitors for cancer therapy.

P300 and CBP are two closely related histone acetyltransferases that are important transcriptional coactivators of many cellular processes. Inhibition of the transcriptional regulator p300/CBP is a promising therapeutic approach in oncology. However, there are no reported single selective p300 or CBP inhibitors to date. In this study, we designed and optimized a series of lysine acetyltransferase p300 selective inhibitors bearing a nucleoside scaffold. Most compounds showed excellent inhibitory activity against p300 with IC50 ranging from 0.18 to 9.90 µM, except for J16, J29, J40, and J48. None of the compounds showed inhibitory activity against CBP (inhibition rate < 50 % at 10 µM). Then the cytotoxicity of the compounds against a series of cancer cells were evaluated. Compounds J31 and J32 showed excellent proliferation inhibitory activity on cancer cells T47D and H520 with desirable selectivity profile of p300 over CBP. These compounds could be promising lead compounds for the development of novel epigenetic inhibitors as antitumor agents.

Antitumor Activity of s-Triazine Derivatives: A Systematic Review.

1,3,5-triazine derivatives, also called s-triazines, are a series of containing-nitrogen heterocyclic compounds that play an important role in anticancer drug design and development. To date, three s-triazine derivatives, including altretamine, gedatolisib, and enasidenib, have already been approved for refractory ovarian cancer, metastatic breast cancer, and leukemia therapy, respectively, demonstrating that the s-triazine core is a useful scaffold for the discovery of novel anticancer drugs. In this review, we mainly focus on s-triazines targeting topoisomerases, tyrosine kinases, phosphoinositide 3-kinases, NADP+-dependent isocitrate dehydrogenases, and cyclin-dependent kinases in diverse signaling pathways, which have been extensively studied. The medicinal chemistry of s-triazine derivatives as anticancer agents was summarized, including discovery, structure optimization, and biological applications. This review will provide a reference to inspire new and original discoveries.

Quinazoline-based hydroxamic acid derivatives as dual histone methylation and deacetylation inhibitors for potential anticancer agents.

Cancer is a common malignant disease with complex signaling networks, which means it is unmanageable to cancer therapy by using single classical targeted drug. Recently, dual- or multitarget drugs have emerged as a promising option for cancer therapies. Although many multifunctional compounds targeting HDAC have been validated, as far as we know, there is no molecule targeting GLP and HDAC synchronously. In the present work, we designed and synthesized a series of quinazoline-based hydroxamic acid derivatives as dual GLP and HDAC inhibitors. These hybrid compounds showed potent enzymatic inhibitory activities against GLP and HDAC1/6 with IC50 values in the nanomolar range of less than 190 nM. Furthermore, most of our compounds displayed significant broad spectrum cytotoxic activities apart from D3 and D8 against all the tested cancer cells with IC50 values less than 50 µM. D1, D6 and D7 showed more potent cytotoxic activities than D2, D4 and D5 in those cancer cells. Especially, compound D7 showed potent inhibitory potency activity against both GLP and HDAC1/6 with IC50 values of 1.3, 89, 13 nM. Besides, D7 exhibited the most potent antiproliferative activity against all the tested cancer cells. Further evaluations indicated that D7 could inhibit the methylation and deacetylation of H3K9 on protein level. Moreover, D7 could induce cancer cell apoptosis, G0/G1 cell cycle arrest, and partly block migration and invasion. All these thorough evaluations warranted D7 as a promising lead compound worth further optimization and development for cancer therapy.

Development of a versatile DNMT and HDAC inhibitor C02S modulating multiple cancer hallmarks for breast cancer therapy.

DNMT and HDAC are closely related to each other and involved in various human diseases especially cancer. These two enzymes have been widely recognized as antitumor targets for drug discovery. Besides, research has indicated that combination therapy consisting of DNMT and HDAC inhibitors exhibited therapeutic advantages. We have reported a DNMT and HDAC dual inhibitor 15a of which the DNMT enzymatic inhibitory potency needs to be improved. Herein we reported the development of a novel dual DNMT and HDAC inhibitor C02S which showed potent enzymatic inhibitory activities against DNMT1, DNMT3A, DNMT3B and HDAC1 with IC50 values of 2.05, 0.93, 1.32, and 4.16 µM, respectively. Further evaluations indicated that C02S could inhibit DNMT and HDAC at cellular levels, thereby inversing mutated methylation and acetylation and increasing expression of tumor suppressor proteins. Moreover, C02S regulated multiple biological processes including inducing apoptosis and G0/G1 cell cycle arrest, inhibiting angiogenesis, blocking migration and invasion, and finally suppressing tumor cells proliferation in vitro and tumor growth in vivo.

Branched rolling circle amplification method for measuring serum circulating microRNA levels for early breast cancer detection.

Serum circulating microRNAs (c-miRNAs) are serving as useful biomarkers for cancer diagnosis. Here, we describe the development of a one-step branched rolling circle amplification (BRCA) method to measure serum c-miRNAs levels for early diagnosis of breast cancer. Four c-miRNAs, c-miRNA16 (c-miR-16), c-miRNA21 (c-miR-21), c-miRNA155 (c-miR-155), and c-miRNA195 (c-miR-195) were isolated from the serum of 49 breast cancer patients and 19 healthy controls. Among them, 45 breast cancer patients and 15 healthy controls were analyzed using one-step BRCA, 4 breast cancer patients and 4 healthy controls were analyzed by quantitative real-time PCR assay [corrected]. The serum levels of c-miR16, c-miR21, c-miR155, and c-miR195 were higher (P < 0.0001) in stage I breast cancer patients than healthy controls. These levels were also higher in several breast cancer molecular subtypes (HER-2 over-expression, Luminal A, Luminal B, and triple negative breast cancer) than in healthy control subjects. The diagnostic accuracy of c-miR16, c-miR21, c-miR155, and c-miR195 for early diagnosis of breast cancer was confirmed by receiver operating characteristic (ROC) curve assay. These results show that the BRCA method can be used to measure serum c-miRNAs levels, and that this method has high accuracy, sensitivity, and specificity. Moreover, both BRCA approach and quantitative real-time PCR (qRT-PCR) method show that the serum levels of c-miR16, c-miR21, c-miR155, and c-miR195 could be used as biomarkers to improve the early diagnosis of breast cancer, and distinguish different breast cancer molecular subtypes.

Olaparib hydroxamic acid derivatives as dual PARP and HDAC inhibitors for cancer therapy.

Olaparib was the first PARP inhibitor approved by the FDA for patients with BRCA-mutated ovarian cancer. Recent studies have demonstrated enhanced anticancer effects of combination therapy consisting of olaparib and HDAC inhibitors. Herein, based on rational drug design strategy, hydroxamic acid derivatives of olaparib were constructed as dual PARP and HDAC inhibitors. These hybrid compounds showed potent inhibitory activities against PARP1/2 and HDAC1/6 with IC50 values in the nanomolar range. Furthermore, compound P1 exhibited broad-spectrum antiproliferative activities in selected human cancer cell lines. Specially, P1 showed more potent activity than olaparib and SAHA in cancer cells MDA-MB-231, HCC1937 and Raji, and 4.1-fold less cytotoxicity compared with SAHA to normal cells MCF-10A. Further mechanism study indicated that P1 could induce the cleavage of PARP and the hyperacetylation of histones, increase the expression of DNA damage biomarker γ-H2AX, decrease the level of BRCA1 and RAD51, and regulate tumor cell growth and apoptosis through modulating both mitochondrial- and death receptor-mediated pathways. Therefore, our study suggested that compounds targeting PARP and HDAC concurrently might be a practical approach for cancer therapy.

Synthesis and biological evaluation of benzimidazole acridine derivatives as potential DNA-binding and apoptosis-inducing agents.

The discovery of new effective DNA-targeted antitumor agent is needed because of their clinical significance. As acridines can intercalate into DNA and benzimidazoles have the ability to bind in the DNA minor groove, a series of novel benzimidazole acridine derivatives were designed and synthesized to be new DNA-targeted compounds. MTT assay indicated that most of the synthesized compounds displayed good antiproliferative activity, among which compound 8l demonstrated the highest activity against both K562 and HepG-2 cells. Further experiments showed that 8l displayed good DNA-binding capability and inhibited topoisomerase I activity. Moreover, compound 8l could induce apoptosis in K562 cell lines through mitochondrial pathway. These data suggested that compound 8l might be potential as new DNA-binding and apoptosis-inducing antitumor agents.

New benzimidazole acridine derivative induces human colon cancer cell apoptosis in vitro via the ROS-JNK signaling pathway.

AIM: To investigate the mechanisms underlying anticancer action of the benzimidazole acridine derivative N-{(1H-benzo[d]imidazol-2-yl)methyl}-2-butylacridin-9-amine(8m) against human colon cancer cells in vitro. METHODS: Human colon cancer cell lines SW480 and HCT116 were incubated in the presence of 8m, and then the cell proliferation and apoptosis were measured. The expression of apoptotic/signaling genes and proteins was detected using RT-PCR and Western blotting. ROS generation and mitochondrial membrane depolarization were visualized with fluorescence microscopy. RESULTS: 8m dose-dependently suppressed the proliferation of SW480 and HCT116 cells with IC50 values of 6.77 and 3.33 µmol/L, respectively. 8m induced apoptosis of HCT116 cells, accompanied by down-regulation of Bcl-2, up-regulation of death receptor-5 (DR5), truncation of Bid, cleavage of PARP, and activation of caspases (including caspase-8 and caspase-9 as well as the downstream caspases-3 and caspase-7). Moreover, 8m selectively activated JNK and p38 without affecting ERK in HCT116 cells. Knockout of JNK1, but not p38, attenuated 8m-induced apoptosis. In addition, 8m induced ROS production and mitochondrial membrane depolarization in HCT116 cells. Pretreatment with the antioxidants N-acetyl cysteine or glutathione attenuated 8m-induced apoptosis and JNK activation in HCT116 cells. CONCLUSION: The new benzimidazole acridine derivative, 8m exerts anticancer activity against human colon cancer cells in vitro by inducing both intrinsic and extrinsic apoptosis pathways via the ROS-JNK1 pathway.

microRNA 21-mediated suppression of Sprouty1 by Pokemon affects liver cancer cell growth and proliferation.

Transcriptional repressor Pokemon is a critical factor in embryogenesis, development, cell proliferation, differentiation, and oncogenesis, thus behaving as an oncogene. Oncomine database suggests a potential correlation between the expressions of Pokemon and Sprouty1. This study investigated the regulatory role of Pokemon in Sprouty1 expression and the effect on liver cancer cell growth and proliferation, revealing a novel miR-21-mediated regulatory circuit. In normal (HL-7702) and cancer (QGY-7703) liver cell lines, Sprouty1 expression is inversely correlated with Pokemon levels. Targeted expression or siRNA-mediated silencing showed that Pokemon is a repressor of Sprouty1 expression at both mRNA and protein levels, but Pokemon cannot affect the promoter activity of Sprouty1. Sprouty1 is a target of miR-21 and interestingly, we found that miR-21 is up-regulated by Pokemon in liver cancer cells. Luciferase reporter assays showed that Pokemon up-regulated miR-21 transcription in a dose-dependent manner, and ChIP assay exhibited a direct binding of Pokemon to the miR-21 promoter at -747 to -399 bp. Site-directed mutagenesis of the GC boxes at -684 to -679 bp and -652 to -647 bp of miR-21 promoter abolished the regulatory activity by Pokemon. Furthermore, we found that the modulation of Pokemon and miR-21 expression affected the growth and proliferation of liver cancer cells QGY-7703. In summary, our findings demonstrate that Pokemon suppresses Sprouty1 expression through a miR-21-mediated mechanism, affecting the growth and proliferation of liver cancer cells. This study recognized miR-21 and Sprouty1 as novel targets of the Pokemon regulatory network.

Homeostatic regulatory role of Pokemon in NF-κB signaling: stimulating both p65 and IκBα expression in human hepatocellular carcinoma cells.

NF-κB consists of p50, p65 (RelA), p52, c-Rel, and RelB, and among them p65 is a representative protein to investigate the regulation and function of this signaling. NF-κB integrates inflammation and carcinogenesis and regulates the expression of a variety of genes in response to immunity, inflammation, and apoptosis. IκBα acts as an inhibitor of NF-κB through forming an inactive NF-κB/IκBα complex. Pokemon is a ubiquitous transcription factor involved in different signaling pathways, playing a pivotal role in cell proliferation, anti-apoptosis, embryonic development, and maintenance. In this study, we found that p65 and IκBα are both novel regulatory targets of Pokemon. Ectopic expression of Pokemon in immortalized liver cells HL7702 enhanced p65 and IκBα expression, whereas silencing of Pokemon in hepatocellular carcinoma cells QGY7703 reduced cellular p65 levels. ChIP assay and targeted mutagenesis revealed that Pokemon directly binds to the element of -434 to -430 bp in p65 promoter and of -453 to -448 bp in IκBα promoter and stimulates luciferase reporter gene expression. Co-transfection of Pokemon with p65 or IκBα promoter-reporter notably enhanced their promoter activity. These data suggest that Pokemon activates the expression of both p65 and IκBα by sequence-specific binding to their promoters and plays a dual role in regulating NF-κB signaling.

Novel synthetic acridine derivatives as potent DNA-binding and apoptosis-inducing antitumor agents.

Acridine derivatives have been explored as DNA-binding anticancer agents. Some derivatives show undesired pharmacokinetic properties and new derivatives need to be explored. In this work, a series of novel acridine analogues were synthesized by modifying previously unexplored linkers between the acridine and benzene groups and their antiproliferative activity and the DNA-binding ability were evaluated. Among these derivatives, compound 5c demonstrated DNA-binding capability and topoisomerase I inhibitory activity. In K562 cell lines, 5c induced apoptosis through mitochondria-dependent intrinsic pathways. These data suggested that compound 5c and other acridine derivatives with modified linkers between the acridine and benzene groups might be potent DNA-binding agents.

Efficient synthesis of RITA and its analogues: derivation of analogues with improved antiproliferative activity via modulation of p53/miR-34a pathway.

A novel approach to synthesize RITA by practical palladium-catalyzed C-C bond-forming Suzuki reactions at room temperature was developed, which was used for deriving a series of substituted tricyclic α-heteroaryl (furan/thiophene) analogues of RITA under mild conditions. These novel analogues showed notable antiproliferative activity against cancer cell lines with wild-type p53 (i.e., HCT116, A549, MCF-7 and K562), but much less activity in HCT116/p53(-/-) cells. In particular, compound 1f demonstrated promising antiproliferative activity compared to RITA, with IC(50) = 28 nM in MCF-7 vs. 54 nM for RITA, and cancer cell selectivity. Compound 1f markedly activated p53 in HCT116 cells at 100 nM, triggering apoptosis. Importantly, we found that both RITA and compound 1f induced G(0)/G(1) cell cycle arrest by up-regulating miR-34a, which in turn down-regulated the expression of cell cycle-related proteins CDK4 and E2F1. In summary, this study reports an effective synthetic approach for RITA and its analogues, and elucidates a novel antiproliferative mechanism of these compounds.

TRIP13, identified as a hub gene of tumor progression, is the target of microRNA-4693-5p and a potential therapeutic target for colorectal cancer.

Colorectal cancer (CRC) is one of the digestive tract malignancies whose early symptoms are not obvious. This study aimed to identify novel targets for CRC therapy, especially early-stage CRC, by reanalyzing the publicly available GEO and TCGA databases. Thyroid hormone receptor interactor 13 (TRIP13) correlated with tumor progression and prognosis of patients after several rounds of analysis, including weighted gene correlation network analysis (WGCNA), and further chosen for experimental validation in cancer cell lines and patient samples. We identified that mRNA and protein levels of TRIP13 increased in CRC cells and tumor tissues with tumor progression. miR-4693-5p was significantly downregulated in CRC tumor tissues and bound to the 3' untranslated region (3'UTR) of TRIP13, downregulating TRIP13 expression. DCZ0415, a small molecule inhibitor targeting TRIP13, induced anti-tumor activity in vitro and in vivo. DCZ0415 markedly suppressed CRC cell proliferation, migration, and tumor growth, promoted cell apoptosis, and resulted in the arrest of the cell cycle. Our research suggests that TRIP13 might play a crucial role in CRC progression and could be a potential target for CRC therapy.

Exploration of acridine scaffold as a potentially interesting scaffold for discovering novel multi-target VEGFR-2 and Src kinase inhibitors.

VEGFR-2 and Src kinases both play important roles in cancers. In certain cancers, Src works synergistically with VEGFR-2 to promote its activation. Development of multi-target drugs against VEGFR-2 and Src is of therapeutic advantage against these cancers. By using molecular docking and SVM virtual screening methods and based on subsequent synthesis and bioassay studies, we identified 9-aminoacridine derivatives with an acridine scaffold as potentially interesting novel dual VEGFR-2 and Src inhibitors. The acridine scaffold has been historically used for deriving topoisomerase inhibitors, but has not been found in existing VEGFR-2 inhibitors and Src inhibitors. A series of 21 acridine derivatives were synthesized and evaluated for their antiproliferative activities against K562, HepG-2, and MCF-7 cells. Some of these compounds showed better activities against K562 cells in vitro than imatinib. The structure-activity relationships (SAR) of these compounds were analyzed. One of the compounds (7r) showed low µM activity against K562 and HepG-2 cancer cell-lines, and inhibited VEGFR-2 and Src at inhibition rates of 44% and 8% at 50µM, respectively, without inhibition of topoisomerase. Moreover, 10µM compound 7r could reduce the levels of activated ERK1/2 in a time dependant manner, a downstream effector of both VEGFR-2 and Src. Our study suggested that acridine scaffold is a potentially interesting scaffold for developing novel multi-target kinase inhibitors such as VEGFR-2 and Src dual inhibitors.

Design, synthesis and evaluation of novel ErbB/HDAC multitargeted inhibitors with selectivity in EGFRT790M mutant cell lines.

Acquired resistance leads to the failure of EGFR TKIs in NSCLC treatment. A novel series of hydroxamic acid-containing 4-aminoquinazoline derivatives as irreversible ErbB/HDAC multitargeted inhibitors for NSCLC therapy had been designed and synthesized, which displayed weak anti-proliferative activity in several EGFR wild-type cancer cell lines (NCI-H838, SK-BR-3, A549, A431) yet retained moderate activity to EGFRT790M resistance mutation harboring NCI-H1975 cells. The mechanistic studies revealed that the representative compound 11e was able to inhibit the phosphorylation of EGFR, up-regulate hyperacetylation of histone H3 and even reduce the expression of EGFR and Akt in NCI-H1975 cells. In further assays, compound 11e also showed moderate anti-proliferative activity in other EGFRT790M harboring tumor cell lines (NCI-H820, Ba/F3_EGFR_Del19-T790M-C797S) and low toxicities in normal cell lines (HL-7702, FHC). This selectivity of designed multitargeted compounds could serve as a potential strategy to circumvent multiple mechanisms of acquired resistance to EGFR-targeted therapy without severe toxicities and side effects resulting from broad inhibition.

IBSP, a potential recurrence biomarker, promotes the progression of colorectal cancer via Fyn/ß-catenin signaling pathway.

Colorectal cancer (CRC) is a frequently occurring digestive system cancer and postoperative tumor metastasis and recurrence are the main reasons for the failure of CRC treatment. The aim of this study was to identifying and validating key genes associated with metastatic recurrence of CRC. RNA expression of three datasets (GSE17538, GSE32323, and GSE29623) was used for biomarker discovery. We identified integrin-binding sialoprotein (IBSP) as a candidate biomarker which was validated in three clinical cohorts (GSE41258, GSE21510, and GSE39582) and our clinical specimens. The results suggested that IBSP expression significantly increased at mRNA and protein levels among CRC cases, which was associated with metastatic recurrence, metastasis, high risk of recurrence, and poor survival in CRC. Consistent results were obtained in CRC cells. The relative level of serum IBSP evidently increased among CRC patients relative to normal controls, and downregulated after operation. As suggested by gene set enrichment analysis (GSEA), the IBSP level was associated with cell-matrix adhesion in CRC. Functional experiments in vitro showed that IBSP promoted the growth and aggressiveness of CRC, and the potential mechanism by which IBSP promoted carcinogenesis of CRC was the abnormal activation of Fyn/ß-catenin signaling pathway. To sum up, findings in the present work indicate that IBSP can serve as the candidate biomarker for the diagnosis, treatment, and prognosis of CRC.

Global mapping of ZBTB7A transcription factor binding sites in HepG2 cells.

ZBTB7A is a known proto-oncogene that is implicated in carcinogenesis and cell differentiation and development. Fully understanding the function of ZBTB7A in cellular processes could provide useful strategies for cancer treatment and development-associated disease therapy. Here, global mapping of ZBTB7A transcription factor binding sites was developed by utilizing microarray technology in HepG2 cells. The data obtained from the microarrays was further validated via chromatin immunoprecipitation-PCR (ChIP-PCR) and real time-PCR, and it was revealed that ZBTB7A may be one of the regulators of neural development. ZBTB7A target signal pathways were identified in signal pathway and GO (Gene Ontology) analyses. This is the first report on the global mapping of ZBTB7A downstream direct targets, and these findings will be useful in understanding the roles of ZBTB7A in cellular processes.

Current discovery strategies for hepatocellular carcinoma therapeutics.

Introduction: The global incidence of hepatocellular carcinoma (HCC) is not expected to decline significantly over the next 30 years. And although the latest gene sequencing studies have established its genetic map, the potentially targetable drivers of HCC are, so far, difficult to identify. To date, only seven drugs have been approved by the FDA for unresectable HCC treatment; thus, effective therapeutic breakthroughs are still needed urgently.Areas covered: In this review, the authors discuss both genetic and epigenetic alterations in HCC and introduce the current progress with some of the representative molecular targeting inhibitors, listing some of the approved drugs for the targets of HCC. The structure-activity relationship of molecules (e.g. thalidomide, bortezomil) used for HCC is also discussed.Expert opinion: Effective therapeutic targets and effective drugs for HCC treatment are an urgent unmet need. Better understanding and characterization of genetic and epigenetic alterations, which are important to hepatocarcinogenesis, may help to understand the molecular pathogenesis of HCC, as well as provide novel therapeutic lead compounds for HCC treatment.

Association study of FGF18 with developmental dyslexia in Chinese population.

Developmental dyslexia (DD) is a neurobiological disorder featured by reading disabilities. In recent years, genome-wide approaches provided new perspectives to discover novel candidate genes of DD. In a previous study, rs9313548 located downstream of FGF18 showed borderline genome-wide significant association with DD. Herein, we selected rs9313548 and 11 independent tag single nucleotide polymorphisms covering gene region of FGF18 to perform association analysis with DD among 978 Chinese dyslexic cases and 998 controls recruited from elementary schools. However, we did not observe any single nucleotide polymorphism exceeding significant threshold. Our preliminary results suggested that FGF18 might not be a susceptibility gene for DD in Chinese population.

Antiproliferative activities of the second-generation antipsychotic drug sertindole against breast cancers with a potential application for treatment of breast-to-brain metastases.

Epidemiological observations have shown that schizophrenia patients after long-term drug treatment exhibited reduced tumor incidences. The potential anticancer effects of antipsychotic drugs are subsequently demonstrated. These drugs are of great interest as agents against untreatable brain metastases because of their ability to traverse the blood-brain barrier (BBB). Most drugs tested thus far are the first-generation antipsychotics (FGAs). But their clinical application may be limited due to high risks of deaths in elderly patients. There is an urgent need to find additional BBB-traversing anticancer agents with lower risks of deaths. In this work, we investigated antitumor activities of eight second-generation-antipsychotic (SGA) drugs, since they exhibit lower mortality rates than FGAs. We discovered that sertindole showed broad antiproliferative activities against seven cancer types including 29 cell-lines and exhibited potent effects toward breast cancer cell-lines, with half maximal concentration to inhibit proliferation by 50% (IC50) as low as 800 nM. We further found that sertindole caused cell death through autophagy-associated apoptosis and its directly-binding inhibition of 5-HT6 involved in this process. In xenotransplant mice, sertindole administration approaching maximal therapeutic dose attenuated breast-tumor growth by 22.7%. Therefore, our study reveals promising anticancer potentials of sertindole against breast cancers, with probable applications for breast-to-brain metastases.