Molecular cloning, characterization, and tissue distribution of c-Myc from blood clam Tegillarca granosa and its role in cadmium-induced stress response.

Cadmium (Cd) pollution threatens the cultivation of the blood clam Tegillarca granosa (T. granosa) in coastal regions of the East China Sea. The molecular mechanisms regulating Cd stress response and detoxification in blood clams are largely unclear. In the present study, the full-length T. granosa c-Myc (Tgc-Myc) cDNA was cloned for the first time. The 3063-bp cDNA consisted of a 129-bp 5' untranslated region (UTR), a 1746-bp 3' UTR, and a 1188-bp open reading frame encoding a predicted protein of 395 amino acid residues. The predicted protein had a calculated molecular weight of 44.9 kDa and an estimated isoelectric point of 6.82. The predicted protein contained an N-terminal transactivation domain and a C-terminal basic helix-loop-helix leucine zipper domain, which are conserved functional domains of c-Myc proteins. Tgc-Myc showed broad tissue distribution in blood clams, with the highest expression detected in the gill and hepatopancreas. Exposure to Cd, a major heavy metal pollutant in coastal regions of the East China Sea, induced Tgc-Myc expression in gill tissues. Tgc-Myc knockdown led to reduced expression of a variety of stress response/detoxification genes in blood clams cultivated in Cd-contaminated seawater. Tgc-Myc knockdown also led to decreased expression of IGF1R, a proto-oncogene that promotes cell proliferation. These findings indicated that Tgc-Myc regulates Cd-induced stress response and detoxification in blood clams. The upregulation of Tgc-Myc may serve as an approach to generate strains with an enhanced detoxification response and consequently a low heavy metal buildup.

Characterization of a novel activating protein-1 (AP-1) gene and the association of its single nucleotide polymorphisms with vibrio resistance in Tegillarca granosa.

The blood clam Tegillarca granosa is a commercial marine bivalve of economic value, accounting for approximately 50% of clam production in China. In recent years, the yield of blood clams has been threatened by bacterial infections caused by marine Vibrio species that thrive under a rising sea temperature. The transcription factor activating protein-1 (AP-1) is emerging as an important player in the innate immunity of marine bivalves against viral or bacterial infections. In this study, the full-length cDNA of a novel T. granosa AP-1 (TgAP-1) was cloned for the first time. The 1591-bp cDNA encoded a protein of 292 amino acid residues with a calculated molecular weight of 32.8 kDa. The TgAP-1 protein contained an N-terminal Jun domain and a C-terminal basic region leucine zipper domain typically found in Jun proteins (a subfamily of AP-1 proteins). TgAP-1 was ubiquitously expressed in T. granosa, with the highest expression detected in the gill and foot, followed by the mantle, hemolymph, and hepatopancreas. Exposure to Vibrio harveyi induced TgAP-1 expression in gill tissues and the expression levels of TgAP-1 of resistant blood clams were always lower than that of control population whether Vibro infection or not. A total of 18 single nucleotide polymorphisms (SNPs) of TgAP-1 were detected in T. granosa. SNP-typing and haplotyping of resistant and susceptible populations revealed that six SNPs (AG type of TgSNP-1, GA type of TgSNP-2, TG type of TgSNP-4, CT type of TgSNP-7, AG type of TgSNP-11, and GA type of TgSNP-12) and four haplotypes (fHap2, fHap3, fHap6, and fHap7) were significantly associated with V. harveyi resistance. Risk assessment showed that fHap2 (CG) and fHap7 (GA) were associated with an increased resistance, while fHap3 (CT) and fHap6 (AG) were associated with an increased susceptibility. The results from this study supported a potential role of TgAp-1 in the anti-Vibro immunity of T. granosa. The discovery of the genetic molecular markers and haplotypes related to Vibrio resistance can provide guidance for selective breeding of T. granosa in the future.

Long Non-coding RNA TMEM220-AS1 Suppressed Hepatocellular Carcinoma by Regulating the miR-484/MAGI1 Axis as a Competing Endogenous RNA.

Long non-coding RNAs (lncRNAs) have a considerable regulatory influence on multiple biological processes. Nevertheless, the role of TMEM220-AS1 in hepatocellular carcinoma (HCC) remains unclear. We used The Cancer Genome Atlas (TCGA) database to analyze the differentially expressed lncRNAs. qRT-PCR was used to verify the results for a large population. The in vitro effects of TMEM220-AS1 on HCC cells were determined using Cell Counting Kit-8 (CCK-8), 5-ethynyl-2'-deoxyuridine (EdU), flow cytometry, and Transwell assays in HCC cells. We used qRT-PCR and western blotting to identify the epithelial-mesenchymal transition (EMT). Moreover, we performed bioinformatics analysis, western blotting, dual luciferase reporter gene assay, RNA pull-down, and RNA binding protein immunoprecipitation (RIP) to investigate the underlying molecular mechanisms of TMEM220-AS1 function. Finally, the function of TMEM220-AS1 was verified in vivo. The results showed that TMEM220-AS1 was expressed at considerably low levels in HCC. It was demonstrated that malignant phenotypes and EMT of HCC cells were promoted by the knock down of TMEM220-AS1 both in vivo and in vitro. TMEM220-AS1, which was detected primarily in the cytoplasm, functioned as an miRNA sponge to bind miR-484 and promote the level of membrane-associated guanylate kinase, WW, and PDZ domain containing 1 (MAGI1), thereby curbing the malignant phenotypes of HCC cells. In conclusion, low levels of TMEM220-AS1 promote proliferation and metastasis through the miR-484/MAGI1 axis in HCC.

lncRNA PRR34-AS1 promotes HCC development via modulating Wnt/ß-catenin pathway by absorbing miR-296-5p and upregulating E2F2 and SOX12.

Hepatocellular carcinoma (HCC) belongs to the most frequent cancer with a high death rate worldwide. Thousands of long non-coding RNAs (lncRNAs) have been confirmed to influence the development of human cancers, including HCC. Nevertheless, the biological role of PRR34 antisense RNA 1 (PRR34-AS1) in HCC remains obscure. Here, we observed via quantitative real-time reverse transcriptase polymerase chain reaction (quantitative real-time RT-PCR) that PRR34-AS1 was highly expressed in HCC cells. Functional assays revealed that PRR34-AS1 promoted HCC cell proliferation, migration, invasion, and epithelial-mesenchymal transition (EMT) process in vitro and facilitated tumor growth in vivo. In addition, western blot analysis and TOP Flash/FOP Flash reporter assays verified that PRR34-AS1 stimulated Wnt/ß-catenin pathway in HCC cells. Furthermore, RNA immunoprecipitation (RIP), RNA pull-down, and luciferase reporter assays uncovered that PRR34-AS1 sequestered microRNA-296-5p (miR-296-5p) to positively modulate E2F transcription factor 2 (E2F2) and SRY-box transcription factor 12 (SOX12) in HCC cells. Importantly, chromatin immunoprecipitation (ChIP) and luciferase reporter assays uncovered that E2F2 transcriptionally activated PRR34-AS1 in turn. Further, rescue experiments reflected that PRR34-AS1 affected HCC progression through targeting miR-296-5p/E2F2/SOX12/Wnt/ß-catenin axis. Our findings found that PRR34-AS1 elicited oncogenic functions in HCC, which indicated that PRR34-AS1 might be a novel therapeutic target for HCC.

Effects of matrine in combination with cisplatin on liver cancer.

Matrine, an alkaloid isolated from Sophora flavescens, promotes tumor cell apoptosis and strengthens the anticancer capacity of chemotherapeutic drugs. The present study aimed to investigate the inhibitory effect and underlying mechanism of matrine in combination with cisplatin on liver cancer progression. Tumor progression was studied in nude mice. The human liver cancer cell line HepG2 was injected into BALB/c nude mice subcutaneously to establish a tumor model. Mice were subsequently treated with matrine, cisplatin, matrine + cisplatin or normal saline. Nude mice and tumor growth were monitored. Tumors were excised and the expression of survivin, caspase-3, caspase-7 and caspase-9 was detected by immunohistochemistry. Western blotting was used to determine the expression of survivin, caspase-3, caspase-7, caspase-9 and X-linked inhibitor of apoptosis protein (XIAP) in tumor tissues. The results demonstrated that matrine exerted anticancer effects in liver cancer-transplanted tumors, as evidenced by decrease in tumor weight and volume. Furthermore, the tumor inhibition rate in mice treated with matrine + cisplatin was 83.3%, whereas it was of 37.5 and 75% in mice treated with matrine or cisplatin alone, respectively. In addition, the expression of survivin and XIAP was significantly downregulated, whereas the expression of caspase-3, caspase-7 and caspase-9 was significantly upregulated in tumor tissues from nude mice treated with matrine + cisplatin, compared with those treated with cisplatin, matrine or normal saline. These findings suggested that the combination of matrine and cisplatin may promote tumor cell apoptosis in liver cancer by activating the caspase apoptosis pathway and suppressing the survivin-associated inhibition of caspase-9.

[Matrine enhances the anticancer effect of cisplatin against hepatocellular carcinoma xenografts in nude mice by influencing expression of survivin/caspase-3].

OBJECTIVE: To investigate the effect and molecular mechanism of cisplatin (DDP) combined with Matrine (Ma;plant alkaloid) against hepatocellular carcinoma using a nude mouse model with xenografted human tumors. METHODS: Twenty-four 6-week old male BALB/c nude mice were subcutaneously injected with HepG2 cells into the axilla, and randomly divided into four groups:control (NS) group,Ma treatment group,DDP treatment group and DDP+Ma combination treatment group. All treatments were delivered via intraperitoneal injection.Changes in whole body weights and tumor volume were assessed by before and after treatment measurements and plotting of growth curves. After 14 days of drug intervention, the mice were sacrificed for collection of tumor tissue and assessment of the tumor inhibition rates for each treatment. Affects on expression of survivin and caspase-3 were assessed by immunohistochemistry. ANOVA test and t-test were performed for the statistical analyses. RESULTS: The tumor inhibition rates for the various treatments were:37.5%,Ma alone;75.0% DDP alone;83.3%,DDP+Ma group DDP combined. The DDP+Ma-induced inhibition was significantly greater than that achieved wit Ma or DDP alone (both P less than 0.05). The average weight of the DDP+Ma group (21.5 g) was lower than that of the NS group (28.5 g) and the Ma group (26.67 g),but higher than that of the DDP group (17.33 g).In addition, the DDP+Ma group also showed more robust general health,as indicated by activity,participation in life routines and appetite,than the DDP group. The rate of positive staining for survivin expression in tumor tissues was significantly lower in the DDP+Ma group (19.58%+/-4.52%) than in the NS group (83.26%+/-15.56%), the Ma group (62.50%+/-8.09%), and the DDP group (38.67%+/-8.26%) (all P less than 0.05).In contrast, the rate of positive staining for Bax expression was significantly higher in the DDP+Ma group (78.26%+/-6.09%) than in the NS group (21.15%+/-3.68%), the Ma group (35.13%+/-10.57%), and the DDP group (65.88%+/-4.81%) (all P less than 0.05). CONCLUSION: Treatment with Ma alone or DDP alone is sufficient to inhibit the growth ofxenografted human hepatocellular carcinoma cells in nude mice. The DDP+Ma combination treatment,however,shows greater inhibitory effect,suggesting that Ma may enhance DDP's anticancer properties. The improved health status of mice treated with DDP+Ma suggests that Ma may reduce DDP toxicity. The mechanism underlying these beneficial treatment effects may involve modulation of survivin/caspase-3 expression and subsequent apoptosis.