Disulfiram enhances the antitumor activity of cisplatin by inhibiting the Fanconi anemia repair pathway / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

A series of chemotherapeutic drugs that induce DNA damage, such as cisplatin (DDP), are standard clinical treatments for ovarian cancer, testicular cancer, and other diseases that lack effective targeted drug therapy. Drug resistance is one of the main factors limiting their application. Sensitizers can overcome the drug resistance of tumor cells, thereby enhancing the antitumor activity of chemotherapeutic drugs. In this study, we aimed to identify marketable drugs that could be potential chemotherapy sensitizers and explore the underlying mechanisms. We found that the alcohol withdrawal drug disulfiram (DSF) could significantly enhance the antitumor activity of DDP. JC-1 staining, propidium iodide (PI) staining, and western blotting confirmed that the combination of DSF and DDP could enhance the apoptosis of tumor cells. Subsequent RNA sequencing combined with Gene Set Enrichment Analysis (GSEA) pathway enrichment analysis and cell biology studies such as immunofluorescence suggested an underlying mechanism: DSF makes cells more vulnerable to DNA damage by inhibiting the Fanconi anemia (FA) repair pathway, exerting a sensitizing effect to DNA damaging agents including platinum chemotherapy drugs. Thus, our study illustrated the potential mechanism of action of DSF in enhancing the antitumor effect of DDP. This might provide an effective and safe solution for combating DDP resistance in clinical treatment.

Deubiquitination complex platform: A plausible mechanism for regulating the substrate specificity of deubiquitinating enzymes

Deubiquitinating enzymes (DUBs) or deubiquitinases facilitate the escape of multiple proteins from ubiquitin‒proteasome degradation and are critical for regulating protein expression levels in vivo. Therefore, dissecting the underlying mechanism of DUB recognition is needed to advance the development of drugs related to DUB signaling pathways. To data, extensive studies on the ubiquitin chain specificity of DUBs have been reported, but substrate protein recognition is still not clearly understood. As a breakthrough, the scaffolding role may be significant to substrate protein selectivity. From this perspective, we systematically characterized the scaffolding proteins and complexes contributing to DUB substrate selectivity. Furthermore, we proposed a deubiquitination complex platform (DCP) as a potentially generic mechanism for DUB substrate recognition based on known examples, which might fill the gaps in the understanding of DUB substrate specificity.

The dichotomous role of immunoproteasome in cancer: Friend or foe?

Immunoproteasome is a variant of proteasome with structural differences in 20S subunits optimizing them for the production of antigenic peptides with higher binding affinity to major histocompatibility complex (MHC)-I molecules. Apart from this primary function in antigen presentation, immunoproteasome is also responsible for the degradation of proteins, both unfolded proteins for the maintenance of protein homeostasis and tumor suppressor proteins contributing to tumor progression. The altered expression of immunoproteasome is frequently observed in cancers; however, its expression levels and effects vary among different cancer types exhibiting antagonistic roles in tumor development. This review focuses on the dichotomous role of immunoproteasome in different cancer types, as well as summarizes the current progression in immunoproteasome activators and inhibitors. Specifically targeting immunoproteasome may be a beneficial therapeutic intervention in cancer treatment and understanding the role of immunoproteasome in cancers will provide a significant therapeutic insight for the prevention and treatment of cancers.

AKT inhibitor Hu7691 induces differentiation of neuroblastoma cells

While neuroblastoma accounts for 15% of childhood tumor-related deaths, treatments against neuroblastoma remain scarce and mainly consist of cytotoxic chemotherapeutic drugs. Currently, maintenance therapy of differentiation induction is the standard of care for neuroblastoma patients in clinical, especially high-risk patients. However, differentiation therapy is not used as a first-line treatment for neuroblastoma due to low efficacy, unclear mechanism, and few drug options. Through compound library screening, we accidently found the potential differentiation-inducing effect of AKT inhibitor Hu7691. The protein kinase B (AKT) pathway is an important signaling pathway for regulating tumorigenesis and neural differentiation, yet the relation between the AKT pathway and neuroblastoma differentiation remains unclear. Here, we reveal the anti-proliferation and neurogenesis effect of Hu7691 on multiple neuroblastoma cell lines. Further evidence including neurites outgrowth, cell cycle arrest, and differentiation mRNA marker clarified the differentiation-inducing effect of Hu7691. Meanwhile, with the introduction of other AKT inhibitors, it is now clear that multiple AKT inhibitors can induce neuroblastoma differentiation. Furthermore, silencing AKT was found to have the effect of inducing neuroblastoma differentiation. Finally, confirmation of the therapeutic effects of Hu7691 is dependent on inducing differentiation in vivo, suggesting that Hu7691 is a potential molecule against neuroblastoma. Through this study, we not only define the key role of AKT in the progression of neuroblastoma differentiation but also provide potential drugs and key targets for the application of differentiation therapies for neuroblastoma clinically.

WSB1 regulates c-Myc expression through β-catenin signaling and forms a feedforward circuit

The dysregulation of transcription factors is widely associated with tumorigenesis. As the most well-defined transcription factor in multiple types of cancer, c-Myc can transform cells by transactivating various downstream genes. Given that there is no effective way to directly inhibit c-Myc, c-Myc targeting strategies hold great potential for cancer therapy. In this study, we found that WSB1, which has a highly positive correlation with c-Myc in 10 cancer cell lines and clinical samples, is a direct target gene of c-Myc, and can positively regulate c-Myc expression, which forms a feedforward circuit promoting cancer development. RNA sequencing results from Bel-7402 cells confirmed that WSB1 promoted c-Myc expression through the β-catenin pathway. Mechanistically, WSB1 affected β-catenin destruction complex-PPP2CA assembly and E3 ubiquitin ligase adaptor β-TRCP recruitment, which inhibited the ubiquitination of β-catenin and transactivated c-Myc. Of interest, the effect of WSB1 on c-Myc was independent of its E3 ligase activity. Moreover, overexpressing WSB1 in the Bel-7402 xenograft model could further strengthen the tumor-driven effect of c-Myc overexpression. Thus, our findings revealed a novel mechanism involved in tumorigenesis in which the WSB1/c-Myc feedforward circuit played an essential role, highlighting a potential c-Myc intervention strategy in cancer treatment.

Cyclin-dependent kinases-based synthetic lethality: Evidence, concept, and strategy

Synthetic lethality is a proven effective antitumor strategy that has attracted great attention. Large-scale screening has revealed many synthetic lethal genetic phenotypes, and relevant small-molecule drugs have also been implemented in clinical practice. Increasing evidence suggests that CDKs, constituting a kinase family predominantly involved in cell cycle control, are synthetic lethal factors when combined with certain oncogenes, such as

Advances in the optimization of the linker in proteolysis-targeting chimeras (PROTAC) / 药学学报

With high selectivity and potency, target protein degradation technology has recently emerged as a strategy for drug discovery and design. Proteolysis-targeting chimeras (PROTAC) function as inducers for the degradation of target proteins and are a research focus in drug development. Current research on PROTAC mainly revolves around the rational design of PROTAC molecules, the discovery of new E3 ubiquitin ligase ligands and improvement in drug targeting. In this review, we focus on the PROTAC linker and its effects on the generation of the E3 enzyme-PROTAC-target protein ternary complex from three standpoints: length, binding site and chemical properties. We discuss the influences of the linker on the efficacy and the selectivity of PROTAC molecules.

Phosphorylation regulates cullin-based ubiquitination in tumorigenesis

Cullin-RING ligases (CRLs) recognize and interact with substrates for ubiquitination and degradation, and can be targeted for disease treatment when the abnormal expression of substrates involves pathologic processes. Phosphorylation, either of substrates or receptors of CRLs, can alter their interaction. Phosphorylation-dependent ubiquitination and proteasome degradation influence various cellular processes and can contribute to the occurrence of various diseases, most often tumorigenesis. These processes have the potential to be used for tumor intervention through the regulation of the activities of related kinases, along with the regulation of the stability of specific oncoproteins and tumor suppressors. This review describes the mechanisms and biological functions of crosstalk between phosphorylation and ubiquitination, and most importantly its influence on tumorigenesis, to provide new directions and strategies for tumor therapy.

ZDHHC12-mediated claudin-3 -palmitoylation determines ovarian cancer progression

The membrane protein claudin-3 (CLDN3) is critical for the formation and maintenance of tight junction and its high expression has been implicated in dictating malignant progression in various cancers. However, the post-translational modification of CLDN3 and its biological function remains poorly understood. Here, we report that CLDN3 is positively correlated with ovarian cancer progression both and Of interest, CLDN3 undergoes -palmitoylation on three juxtamembrane cysteine residues, which contribute to the accurate plasma membrane localization and protein stability of CLDN3 Moreover, the deprivation of -palmitoylation in CLDN3 significantly abolishes its tumorigenic promotion effect in ovarian cancer cells. By utilizing the co-immunoprecipitation assay, we further identify ZDHHC12 as a CLDN3-targating palmitoyltransferase from 23 ZDHHC family proteins. Furthermore, the knockdown of ZDHHC12 also significantly inhibits CLDN3 accurate membrane localization, protein stability and ovarian cancer cells tumorigenesis Thus, our work reveals -palmitoylation as a novel regulatory mechanism that modulates CLDN3 function, which implies that targeting ZDHHC12-mediated CLDN3 -palmitoylation might be a potential strategy for ovarian cancer therapy.

Targeting slug-mediated non-canonical activation of c-Met to overcome chemo-resistance in metastatic ovarian cancer cells

Metastasis-associated drug resistance accounts for high mortality in ovarian cancer and remains to be a major barrier for effective treatment. In this study, SKOV3/T4, a metastatic subpopulation of ovarian cancer SKOV3 cells, was enriched to explore potential interventions against metastatic-associated drug resistance. Quantitative genomic and functional analyses were performed and found that slug was significantly increased in the SKOV3/T4 subpopulation and contributed to the high resistance of SKOV3/T4. Further studies showed that slug activated c-Met in a ligand-independent manner due to elevated levels of fibronectin and provoked integrin V function, which was confirmed by the significant correlation of slug and p-Met levels in 121 ovarian cancer patient samples. Intriguingly, c-Met inhibitor(s) exhibited greatly enhanced anti-cancer effects in slug-positive ovarian cancer models both and . Additionally, IHC analyses revealed that slug levels were highly correlated with reduced survival of ovarian cancer patients. Taken together, this study not only uncovers the critical roles of slug in drug resistance in ovarian cancer but also highlights a promising therapeutic strategy by targeting the noncanonical activation of c-Met in slug-positive ovarian cancer patients with poor prognosis.

Advances in hyperprogressive disease of PD-1/PD-L1 antibody drugs and rational drug therapy / 药学学报

With the significant breakthrough that programmed cell death 1 (PD-1)/programmed cell death 1 ligand 1 (PD-L1) antibody drugs achieved promising clinical outcomes across various tumor types, immunotherapy targeting immune checkpoint has been considered a promising way to treat cancer. However, most recently studies suggest that the hyperprogressive disease occurred frequently during the therapy of using PD-1/PD-L1 antibody drugs and has become an urgent problem to be solved. In this review, we summarize the progress and potential reasons of hyperprogressive disease caused by PD-1/PD-L1 blockade, and further discuss its application based on the rational use of biomarkers for searching the benefit patients.

Effects of RNA interference of FABP5 on subcutaneous tumor of human hepatocellular carcinoma cell line HepG2 transplanted in nude mice / 中国病理生理杂志

AIM:To investigate the effect of recombinant lentiviral vector for RNA interference (RNAi) on the expression of fatty acid-binding protein 5 (FABP5) gene in hepatocellular carcinoma HepG2 cells and tumor formation in nude mice.METHODS:RNAi lentiviral vector was used in the experiment.Human hepatocellular carcinoma HepG2 cells were divided into 3 groups:the HepG2 cells in experimental group were transfected with the recombinant lentivirirus vector LV-shRNA-FABP5, the cells in negative control group were transfected with a control lentiviral vector LV-shRNA-NC, and the cells in normal control group were without any treatment.The nude mice were randomly divided into 3 groups.The growth of the transplanted tumor cells in the nude mice was observed.The tumor growth curve, volume and weight were de-termined 4 weeks after the cell inoculation.The expression of FABP5 was detected by real-time PCR, Western blot and im-munohistochemical staining.RESULTS:Transfection of the lentiviral vector FABP5-shRNA obviously reduced FABP5 ex-pression in the HepG2 cells.Tumor formation was all positive in the 3 groups of the nude mice inoculated with the tumor cells.Compared with normal control group and negative control group, the tumor growth slowed significantly in experimental group with smaller volume and weight.FABP5 expression in the transplanted tumor tissues was significantly down-regulated at mRNA and protein levels in experimental group as compared with normal control group and negative control group. CONCLUSION:RNAi-induced down-regulation of FABP5 effectively inhibits the growth of transplanted hepatocellular carcinoma, suggesting that FABP5 gene may be an effective target for gene therapy in treating liver cancer.

Detection and significance of the main nutritional ingredients of tree shrew’ s milk / 中国比较医学杂志

Objective To explore the basic ingredients of the tree shrew’ s( Tupaia belangeri) milk and compare with the dairy ingredients of other milks.Methods We select ten seed tree shrews after delivery ( 1 ~21 ) d with lactation mother tree shrews, and use artificial passive breastfeeding method let the young tree shrews suck breast milk,we took the milk from the young tree shrews in the stomach, directly using aseptic operation with a syringe immediately, once every two days, for consecutive three to five times, and a total of 18 mL milk was taken from each seed tree shrew.Then the milk was detected according to the national standard method for component testing.Results The total solid content of the tree shrew’ s milk was 43.63%, including 26.01%of fat, 10.41%of protein, 0.45% of lactose and 0.99%of ash content.Compared with cow's milk, the tree shrew’ s milk contained 3.36 times of total solid contents, 1.24 times of ash, 2.74 times of protein, 6.67 times of fat, and 0.09 times of lactose.Compare with baby formula milk, the tree shrew’ s milk contained 1.44 times of total solid contents, 0.20 times of ash, 0.58 times of protein, 1.53 times of fat, and 0.06 times of lactose.The trace mineral composition of the tree shrew’ s milk showed that the calcium, phosphorus, potassium, sodium, magnesium, and iron contents were 1.83 times, 2.73 times, 1.25 times, 1.93 times, 1.28 times, and 1.48 times higher than those in the cow's milk, and were 0.66 times, 0.85 times, 0.34 times, 0.26 times, 0.85 times, 0.24 times lower than those in baby formula milk.Conclusions The main nutrients of tree shrew’ s milk is of high fat, high protein and low sugar, and it can provide a basis for tree shrews artificial brood and breeding work.

Effects of RNA interference targeting CDC25a gene on proliferation of human liver cancer HepG2 cells / 中国病理生理杂志

[ ABSTRACT] AIM:To investigate the effect of silencing cell division cycle 25a ( CDC25a) gene on the prolifera-tion of human hepatoma HepG2 cells.METHODS:CDC25a gene in human hepatoma HepG2 cells was silenced by RNA interference.Real-time PCR was applied to detect the expression of CDC25a, cyclin E and CDK2 at mRNA levels in the HepG2 cells.Western blotting was applied to detect the expression of CDC25a at protein level.In addition, MTT assay, Giemsa staining and flow cytometry were used to measure the proliferation of human hepatoma HepG2 cells.RESULTS:The expression of CDC25a at mRNA and protein levels in RNA silence group was lower than those in negative control group and normal control group (P<0.05).The mRNA expression of cyclin E and CDK2 in silence group was lower than that in negative control group and normal control group (P<0.05).The cell proliferation in silence group was lower than that in negative control group and normal control group ( P<0.05) .The results of flow cytometry revealed that the cells in silence group were blocked in G1 phase.CONCLUSION:Infection of LV-CDC25a-RNAi recombinant to the HepG2 cells effec-tively inhibits the CDC25a gene expression and the proliferation of human hepatoma cells, and arrests the cells in G1 phase, suggesting that CDC25a gene may be a key target for the treatment of liver cancer.

Changes of Kupffer cells during tree shrew chronically infected with hep-atitis B virus / 中国病理生理杂志

AIM:To explore the changes and significance of Kupffer cells in the process of tree shrew chroni -cally infected with hepatitis B virus (HBV).METHODS:The animals were divided into 3 groups.Group A consists of 6 tree shrews that were identified as persistently infected with HBV;group B consists of 3 tree shrews that were suspected as persistently infected with HBV;group C consists of 4 tree shrews that were not inoculated with HBV and were applied as normal controls.Liver biopsies were collected regularly from all animals , and the Kupffer cells were isolated , purified and primarily cultured.The techniques of flow cytometry , immunohistochemistry, lysosomal fluorescent probe staining and real-time RT-PCR were applied to determine the number and function of these Kupffer cells .RESULTS: The result showed that the count and proportion of CD 163+cells in group A were significantly higher than those in group B and group C ( P<0.05).Meanwhile, the fluorescence intensity levels of lysosomal , the number of lysozyme-positive cells and the mRNA ex-pression level of TNF-αin the Kupffer cells in group A were significantly lower than those in group B and group C ( P<0.05).CONCLUSION:Kupffer cells may play a regulatory role during host’s chronic HBV infection.

The expression and significance of MCM7 protein in hepatocellu-lar carcinoma tissues of human, rat and tree shrew / 中国肿瘤临床

Objective:To test the expression of Minichromosome maintenance complex component 7(MCM7) protein in hepato-cellular carcinoma(HCC) of different species including human, rat and tree shrew (tupaia) by cross-species oncogenomics approach, and to investigate the relationship between the expression of MCM7 and the development of hepatocellular carcinoma and its clinical significance. Methods:Western blot and Immunohistochemistry were applied to detect the expression levels of MCM7 protein in HCC tissues,corresponding HCC-adjacent liver tissues and normal liver tissues collected from different species including human, rat and tree shrew, respectively. The clinicopathologic factors were also analyzed with the results of Immunohistochemistry. Results:Western blot analysis showed that the expression of MCM7 protein in HCC tissues of human and rat were higher than that in corresponding HCC-ad-jacent liver tissues and normal liver tissues, respectively and significantly (P0.05).There was also no significant difference between HCC-adjacent liver tis-sues and normal liver tissues in three species (P>0.05). Immunohistochemical analysis showed that MCM7 protein was mainly ex-pressed in nucleus of HCC cells, and the positive rate of MCM7 protein in HCC tissues of human, rat and tree shrew were significantly higher than that in corresponding HCC-adjacent liver tissues and normal liver tissues, respectively (P0.05). Moreover, the protein level of MCM7 was intimately related to patient's HCC stage, extrahepatic metastases and postoperative recurrence (P<0.05). Conclusion:MCM7 protein might play a pivotal role in hepatocarcinogenesis. In addition, it was probably related to patient's HCC stage, extrahepatic metastases and postoperative recurrence. It seems very likely that MCM7 may be applied as a new molecular target in HCC prevention and treat-ment.

Expression of epidermal fatty acid-binding protein in cross-species hepatocellular carcinoma / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To evaluate the utility of the cross-species screening strategy for investigating key molecule(s) involved in onset and progression of hepatocellular carcinoma (HCC).</p><p><b>METHODS</b>HCC-related molecule data from our previous studies and in the literature were collected to establish a cross-species dataset. Tissue samples of HCC, non-HCC surrounding liver (para-HCC), and normal liver that were collected from humans, tree shrews and rats. The genes reported to have the most differential expression in HCC were verified by analyzing the mRNA and protein levels by reverse transcription-polymerase chain reaction (RT-PCR) and Western blotting, respectively.</p><p><b>RESULTS</b>The cross-species dataset of HCC-related molecules included four genes: epidermal fatty acid-binding protein (E-FABP), liver (L)-FABP, tyrosine a-ketoglutarate transaminase (TKT), and cytokeratin (CK8). In humans, E-FABP mRNA expression was significantly higher (P less than 0.05) in HCC (0.87+/-0.14 vs. para-HCC: 0.64+/-0.12 and normal liver: 0.67+/-0.07; F=20.910). Similar results were obtained in tree shrew (HCC: 0.87 +/- 0.25 vs. para-HCC: 0.73 +/- 0.19 and normal liver: 0.68+/-0.19; F=3.807) and rat (HCC: 0.97+/-0.22 vs. para-HCC: 0.78+/-0.16 and normal liver: 0.80 +/- 0.13; F=4.482). The Western blotting analyses revealed a similar statistically significant trend.</p><p><b>CONCLUSION</b>The cross-species screening strategy for tumor genes may represent a feasible and convenient process of identifying key molecule(s) for human HCC. E-FABP may be a particularly crucial molecule for hepatocarcinogenesis.</p>

Factors influencing long-term hepatitis B virus infection of the tree shrew (Tupaia belangeri chinensis) as an in vivo model of chronic hepatitis B / 中华肝脏病杂志

<p><b>OBJECTIVE</b>To determine the methods for establishing an in vivo model of long-term hepatitis B virus (HBV) infection in the Chinese tree shrew (Tupaia belangeri chinensis).</p><p><b>METHODS</b>Seventy-seven neonate (1-3 days old) and 49 young adult (2 weeks to 1 year old) tree shrews were inoculated with different HBV sources (chronic hepatitis B (CHB) human patient serum, single or pooled; HBV-infected tree shrew serum, single only; HBV-infected HepG2.2.15 cells' culture medium supernatant; HBV genome-transfected HepG2.2.15 cells' culture medium supernatant) through various routes of injection (subcutaneous, intraperitoneal, and direct liver via abdominal skin; adults also received intravenous and indirect liver via spleen). Serum and liver biopsies were collected from the animals at various time points post-inoculation for detection of HBV markers by fluorescence quantitative polymerase chain reaction, enzyme-linked immunosorbent assay, time-resolved immunofluorescence, Southern blotting, dot blotting, immunohistochemistry, and microscopy.</p><p><b>RESULTS</b>Among the neonatal group of tree shrews, six (7.8%) were confirmed as HBV-infected for more than 72 (up to 228) weeks after inoculation and another seven (9.1%) were suspected of persistent infections. None of the young adult tree shrews developed persistent infection. Inoculation with single-source serum from either CHB humans or tree shrews were responsible for the most cases of infections, and the subcutaneous injection produced more infections than the other inoculation routes. The most reliable methods of determining HBV infection status were detection of serum HBV immunoreactive markers and intrahepatic HBV DNA.</p><p><b>CONCLUSION</b>In order to establish an in vivo model of CHB in the tree shrew, the animals should be inoculated in the neonatal period using subcutaneous injection.</p>

Using bioinformatics to screen common key genes in hepatocellular carcinoma in human and rat / 中华肝胆外科杂志

Objective To use bioinformatics methods to analyze large amounts of data generated by gene chips and to screen common key genes in hepatocellular carcinoma in human and rat.Methods For search of the medical literature,3 sets of gene chip with data which met our predetermined criteria were downloaded from the GEO database.The data were standardized by using the bioconductor and R version of the 2.10.1 version.The original data of the affymetrix platform were normalized with background correction,standardized and transformed into log2 by using the algorithm of the affy packages RMA.The TTEST function of the excel was then used to calculate the significance of each gene.The DAVID was used for gene ID conversion and a table was established for samples and the corresponding gene expression data.A meta analysis was performed to calculate the common genes of human and rat.An enrichment regulation pathway was gained with the KEGG in the DAVID library. Results There were 26 common expression genes in the development process of hepatocellular carcinoma in human and rat.Five of these genes were up-regulation genes,while twenty-one were down-regulation genes.An enrichment pathway,which is a focal adhesion pathway,was found and this pathway has been reported to be associated with development of hepatocellular carcinoma.Conclusion With bioinformatics,we were able to screen common key genes and a pathway which were closely related to development of hepatocellular carcinoma in human and rat.

Chemical constituents of Humulus scandens / 中草药

Objective: To study the chemical constituents of Humulus scandens. Methods: The compounds were isolated and repeatedly purified by silica gel, TLC, and Sephadex LH-20 column chromatography, and their structures were elucidated on the basis of physicochemical constants and spectral analysis. Results: Eleven compounds were obtained and elucidated as (24R)-stigmast-7, 22(E)-dien-3β- ol (1), daucesterol (2), stigmast-3, 6-dione (3), epidioxyergosta-6, 22-dine-3β-ol (4), stigmasterol (5), soya-erebroside II (6), oleanolic acid (7), bis-(2-ethylhexyl) phthalate (8), scopoletin (9), betulimicaciol (10), and soya-erebroside I (11). Conclusion: The compounds 1, 3, 4 and 6-11 are isolated from the plants of Humulus Linn. for the first time.