Overexpressed NEDD8 as a potential therapeutic target in esophageal squamous cell carcinoma

Objective:The hyperactivated neddylation pathway plays an important role in tumorigenesis and is emerging as a promising anticancer target.We aimed to study whether NEDD8(neural precursor cell expressed,developmentally down-regulated 8)might serve as a therapeutic target in esophageal squamous cell carcinoma(ESCC).Methods:The clinical relevance of NEDD8 expression was evaluated by using The Cancer Genome Atlas(TCGA)database and tissue arrays.NEDD8-knockdown ESCC cells generated with the CRISPR/Cas9 system were used to explore the anticancer effects and mechanisms.Quantitative proteomic analysis was used to examine the variations in NEDD8 knockdown-induced biological pathways.The cell cycle and apoptosis were assessed with fluorescence activated cell sorting.A subcutaneous-transplantation mouse tumor model was established to investigate the anticancer potential of NEDD8 silencing in vivo.Results:NEDD8 was upregulated at both the mRNA and protein expression levels in ESCC,and NEDD8 overexpression was associated with poorer overall patient survival(mRNA level:P=0.028,protein level:P=0.026,log-rank test).Downregulation of NEDD8 significantly suppressed tumor growth both in vitro and in vivo.Quantitative proteomic analysis revealed that downregulation of NEDD8 induced cell cycle arrest,DNA damage,and apoptosis in ESCC cells.Mechanistic studies demonstrated that NEDD8 knockdown led to the accumulation of cullin-RING E3 ubiquitin ligases(CRLs)substrates through inactivation of CRLs,thus suppressing the malignant phenotype by inducing cell cycle arrest and apoptosis in ESCC.Rescue experiments demonstrated that the induction of apoptosis after NEDD8 silencing was attenuated by DR5 knockdown.Conclusions:Our study elucidated the anti-ESCC effects and underlying mechanisms of NEDD8 knockdown,and validated NEDD8 as a potential target for ESCC therapy.

Lipidomics reveals carnitine palmitoyltransferase 1C protects cancer cells from lipotoxicity and senescence

Lipotoxicity, caused by intracellular lipid accumulation, accelerates the degenerative process of cellular senescence, which has implications in cancer development and therapy. Previously, carnitine palmitoyltransferase 1C(CPT1C), a mitochondrial enzyme that catalyzes carnitinylation of fatty acids, was found to be a critical regulator of cancer cell senescence. However, whether loss of CPT1C could induce senescence as a result of lipotoxicity remains unknown. An LC/MS-based lipidomic analysis of PANC-1,MDA-MB-231, HCT-116 and A549 cancer cells was conducted after siRNA depletion of CPT1C. Cellular lipotoxicity was further confirmed by lipotoxicity assays. Significant changes were found in the lipidome of CPT1C-depleted cells, including major alterations in fatty acid, diacylglycerol, triacylglycerol, oxidative lipids, cardiolipin, phosphatidylglycerol, phosphatidylcholine/phosphatidylethanolamine ratio and sphingomyelin. This was coincident with changes in expressions of mRNAs involved in lipogenesis.Histological and biochemical analyses revealed higher lipid accumulation and increased malondialdehyde and reactive oxygen species, signatures of lipid peroxidation and oxidative stress. Reduction of ATP synthesis, loss of mitochondrial transmembrane potential and down-regulation of expression of mitochondriogenesis gene m RNAs indicated mitochondrial dysfunction induced by lipotoxicity, which could further result in cellular senescence. Taken together, this study demonstrated CPT1C plays a critical role in the regulation of cancer cell lipotoxicity and cell senescence, suggesting that inhibition of CPT1C may serve as a new therapeutic strategy through induction of tumor lipotoxicity and senescence.

Identification of human LDHC4 as a potential target for anticancer drug discovery

One of the distinct hallmarks of cancer cells is aerobic glycolysis(Warburg effect). Lactate dehydrogenase A(LDHA) is thought to play a key role in aerobic glycolysis and has been extensively studied, while lactate dehydrogenase C(LDHC), an isoform of LDHA, has received much less attention.Here we showed that human LDHC was significantly expressed in lung cancer tissues, overexpression of Ldhc in mice could promote tumor growth, and knock-down of LDHC could inhibit the proliferation of lung cancer A549 cells. We solved the first crystal structure of human LDHC4 and found that the activesite loop of LDHC4 adopted a distinct conformation compared to LDHA4 and lactate dehydrogenase B4(LDHB4). Moreover, we found that(ethylamino)(oxo)acetic acid shows about 10 times selective inhibition against LDHC4 over LDHA4 and LDHB4. Our studies suggest that LDHC4 is a potential target for anticancer drug discovery and(ethylamino)(oxo)acetic acid provides a good start to develop lead compounds for selective drugs targeting LDHC4.

DNA G-quadruplex and its potential as anticancer drug target

G-quadruplex secondary structures are four-stranded globular nucleic acid structures form in the specific DNA and RNA G-rich sequences with biological significance such as human telomeres,oncogene-promoter regions,replication initiation sites,and 5′and 3′-untranslated(UTR)regions.The non-canonical G-quadruplex secondary structures can readily form under physiologically relevant ionic conditions and are considered to be new molecular target for cancer therapeutics.This review discusses the essential progress in our lab related to the structures and functions of biologically relevant DNA G-quadruplexes in human gene promoters and telomeres,and the opportunities presented for the development of G-quadruplex-targeted smallmolecule drugs.

Impairment of pre-mRNA splicing in liver disease: Mechanisms and consequences

Pre-mRNA splicing is an essential step in the process of gene expression in eukaryotes and consists of the removal ofintrons and the linking of exons to generate mature mRNAs. This is a highly regulated mechanism that allows the alternative usage of exons, the retention ofintronic sequences and the generation of exonic sequences of variable length. Most human genes undergo splicing events, and disruptions of this process have been associated with a variety of diseases, including cancer. Hepatocellular carcinoma (HCC) is a molecularly heterogeneous type of tumor that usually develops in a cirrhotic liver. Alterations in pre-mRNA splicing of some genes have been observed in liver cancer, and although still scarce, the available data suggest that splicing defects may have a role in hepatocarcinogenesis. Here we briefly review the general mechanisms that regulatepre-mRNA splicing, and discuss some examples that illustrate how this process is impaired in liver tumorigenesis, and may contribute to HCC development. We believe that a more thorough examination of pre-mRNA splicing is still needed to accurately draw the molecular portrait of liver cancer. This will surely contribute to a better understanding of the disease and to the development of new effective therapies.

The impact of the provincial reimbursement scheme on the use of targeted anticancer medications in Zhejiang,China:a controlled interrupted time-series analysis

To alleviate problems with access and affordability,six targeted anticancer medications(TAMs)were listed in the Provincial Reimbursement Drug List(PRDL)for the first time in Zhejiang,China in February 2015.In the present study,we aimed to evaluate the implementation of the PRDL policy on TAMs use.Using the pharmaceutical procurement data of these six listed TAMs(study group)and four unlisted TAMs(control group)from 22 tertiary hospitals in Zhejiang,China dated between January 2014 and February 2017,interrupted time-series analysis was adopted to examine differences in the average hospital purchasing volume(HPV)and the average hospital purchasing spending(HPS)between the two groups.The average daily cost of listed TAMs in the study group was decreased after April 2015.After enlistment,the average HPV per month was significantly increased by 34.6 defined daily doses(DDDs)(P<0.001),and the average HPS per month was significantly increased by USD 6614.9(P<0.001)for the listed TAMs in the study group(n=6).Neither the average HPV nor the average HPS changed significantly for the unlisted TAMs in the control group(n=4).The PRDL policy showed positive effects on improving patients’affordability and promoting access to TAMs in Zhejiang.The government should conduct further price negotiations and include more TAMs with clinical benefits into reimbursement schemes to relieve patients’financial burden and promote access.

Editorial for targets and anticancer drug research

The research for antitumor therapeutics is a timeless topic and keeps pace with times,especially chemotherapy and target therapy.Drug target identification is a key step in the development of effective therapeutic agents.In this issue,we present the current status of some validated and potential targets in drug discovery for developing therapeutic agents as well as

Targeted peptide-Au cluster binds to epidermal growth factor receptor (EGFR) in both active and inactive states： a clue for cancer inhibition through dual pathways

The epidermal growth factor receptor （EGFR） has become an important target protein in anticancer drug development. Meanwhile, peptide-Au cluster has been proposed as potential targeted nano-drug assembled by targeting peptide. Here, we designed and synthesized a novel peptide-Au cluster as AuloPeptides to target to EGFR. We found AumPeptides could target to the natural binding sites of all EGFRs at mem- brane in both active and inactive states by molecular simulations. Its targeted ability was further verified by the co-localization and blocking experiments. We also study the configuration modifications of both active and inactive EGFRs after binding by AumPeptides. For active EGFR, the absorbed AuloPeptide5 might replace the natural ligand in EGFR endocytosis process. Then, the peptide-Au cluster in endochylema could inhibit the cancer relating enzyme activity including thioredoxin reductasel （TrxR1） and induce the oxidative stress mediated apoptosis in tumor cells. For inactive EGFR, it was retained in inactive state by Au10 Peptides binding to inhibit dimerization of EGFR for anticancer. Both pathways might be applied in anticancer drug development based on the theoretical and experimental study here.

Design and synthesis of biotinylated dimethylation of alkannin oxime derivatives

DMAKO-05,a novel dimethylation of alkannin oxime derivative,exhibits remarkable anticancer activity as well as excellent cellular selectivity and thus has been considered as a promising antineoplastic agent for colorectal carcinoma and melanoma.However,its potent cytotoxicity is not closely associated with reactive oxygen species（ROS） and bioreductive alkylation.Its specific antitumor target（s） has still remained elusive.To recognize the molecular target（s） of DMAKO-05 and its analogs,four biotinylated DMAKO derivatives were designed and prepared.The biotin moiety was successfully introduced in the molecule through a modified Mitsunobu reaction,which kept its anticancer activity.Moreover,the cellbased investigation demonstrated that replacement of the linker C4 chain with another alkyl chain（C6 or C8） gave rise to the enhancement of cytotoxicity.Among these biotinyl derivatives,both compound 16 and 8c exhibited more potent anticancer activity than DMAKO-05 against MCF-7 cells and were comparatively effective to alkannin toward HCT-15 cells.As expected,they might be thought as ideal chemical probes.Collectively,our present work could provide an available approach for the identification of the potential antineoplastic target（s） of DMAKO derivatives.

Effect of Trastuzumab on the Micellization Properties, Endocytic Pathways and Antitumor Activities of Polyurethane-based Drug Delivery System

Polyurethane micelles（PM）-based nanovehicles have shown great potential in targeted delivery of therapeutics and diagnostics into tumors.However,the pathways of PMs entering cancer cells and the action mechanism of targeting ligands have yet to be understood.In this contribution,the actively-targeted PM were developed using trastuzumab as a model targeting group.It was found that PM were mainly taken up by SKOV-3 tumor cells via a micropinocytosis process,while the incorporation of trastuzumab to PM enabled a receptor-mediated endocytosis of nanocarriers in cancer cells,leading to more efficient cell entry and enhanced anticancer efficacy of chemotherapeutic drugs both in vitro and in vivo.This study is advantageous to the understanding of the action mechanism of trastuzumab,and significant for the construction of improved formulations for targeted delivery and precise therapy.