Naja atra venom peptide reduces pain by selectively blocking the voltage-gated sodium channel Nav1.8.

The voltage-gated sodium channel Nav1.8 is preferentially expressed in peripheral nociceptive neurons and contributes to inflammatory and neuropathic pain. Therefore, Nav1.8 has emerged as one of the most promising analgesic targets for pain relief. Using large-scale screening of various animal-derived toxins and venoms for Nav1.8 inhibitors, here we identified µ-EPTX-Na1a, a 62-residue three-finger peptide from the venom of the Chinese cobra (Naja atra), as a potent inhibitor of Nav1.8, exhibiting high selectivity over other voltage-gated sodium channel subtypes. Using whole-cell voltage-clamp recordings, we observed that purified µ-EPTX-Na1a blocked the Nav1.8 current. This blockade was associated with a depolarizing shift of activation and repolarizing shift of inactivation, a mechanism distinct from that of any other gating modifier toxin identified to date. In rodent models of inflammatory and neuropathic pain, µ-EPTX-Na1a alleviated nociceptive behaviors more potently than did morphine, indicating that µ-EPTX-Na1a has a potent analgesic effect. µ-EPTX-Na1a displayed no evident cytotoxicity and cardiotoxicity and produced no obvious adverse responses in mice even at a dose 30-fold higher than that producing a significant analgesic effect. Our study establishes µ-EPTX-Na1a as a promising lead for the development of Nav1.8-targeting analgesics to manage pain.

Shellfish toxins targeting voltage-gated sodium channels.

Voltage-gated sodium channels (VGSCs) play a central role in the generation and propagation of action potentials in excitable neurons and other cells and are targeted by commonly used local anesthetics, antiarrhythmics, and anticonvulsants. They are also common targets of neurotoxins including shellfish toxins. Shellfish toxins are a variety of toxic secondary metabolites produced by prokaryotic cyanobacteria and eukaryotic dinoflagellates in both marine and fresh water systems, which can accumulate in marine animals via the food chain. Consumption of shellfish toxin-contaminated seafood may result in potentially fatal human shellfish poisoning. This article provides an overview of the structure, bioactivity, and pharmacology of shellfish toxins that act on VGSCs, along with a brief discussion on their pharmaceutical potential for pain management.

MiR-1286 inhibits lung cancer growth through aerobic glycolysis by targeting PKM2.

Introduction: This study aims to explore the effects of microRNA-1286 (miR-1286) on the development of non-small cell lung cancer (NSCLC) via the aerobic glycolysis pathway by targeting pyruvate kinase muscle isozyme M2 (PKM2). Material and methods: The mRNA levels of miR-1286 in NSCLC tissues and mouse tumor tissues were detected by q-PCR. MiR-1286 was knocked down and overexpressed separately in A549 cells. The effect of miR-1286 on cell proliferation was determined by CCK8 assay. Western blotting was used to measure the expression of PKM2 protein. Lactate production assay was used to detect the aerobic glycolysis in A549 cells. The effect of miR-1286 in vivo was determined by xenograft assay. Results: The mRNA level of miR-1286 decreased in NSCLC tissues compared with paired, tumor adjacent normal tissues. In addition, miR-1286 inhibited A549 cell proliferation in vitro. Moreover, knockdown of miR-1286 increased PKM2 expression and lactate production. Thus, miR-1286 expression negatively correlated with PKM2 in A549 cells. At the same time, in vivo experiments also showed that miR-1286 suppressed the growth of A549 cells and PKM2 was the target gene of miR-1286. Conclusions: These data show that miR-1286 inhibits lung cancer proliferation via aerobic glycolysis by targeting PKM2, which suggests that the functions of miR-1286 in NSCLC may play a key role in tumor progression and that miR-1286 can be a promising predictive biomarker and potential therapeutic target for NSCLC.

Comprehensive analysis of serum tumor markers and BRCA1/2 germline mutations in Chinese ovarian cancer patients.

BACKGROUND: The serum tumor markers has been widely used in ovarian cancer diagnosis. BRCA1/2 germline mutations are the most common predisposing factors for ovarian cancer development. This study aimed to comprehensively investigate serum tumor markers and BRCA1/2 germline mutations and analyze their associations with ovarian cancer. METHODS: Levels of 11 serum tumor markers were examined in ovarian cancer patients and controls with benign gynecologic diseases. By integrating multiplex PCR and next-generation sequencing technologies, BRCA1/2 germline mutations were analyzed and confirmed by Sanger sequencing. The discriminative models with serum tumor markers and BRCA1/2 mutation status were constructed for ovarian cancer detection and patient stratification. RESULTS: Among 11 markers, six of them were significantly elevated and only beta-human chorionic gonadotropin (ß-HCG) was significantly reduced in ovarian cancer patients. A total of 54 (23.3%) ovarian cancer patients were found to harbor BRCA1/2 deleterious mutations, and BRCA1/2 mutations were significantly associated with Hereditary Breast and Ovarian Cancer-related tumors and family history of cancer. Carbohydrate antigen 125 showed a good performance in ovarian cancer detection as a single marker (AUC = 0.799), while a panel of eight markers showed a good performance in BRCA1 mutation detection with an AUC value of 0.974. In addition, a panel of five serum tumor markers combined with BRCA1/2 mutation status showed a good performance in lymph node metastasis prediction (AUC = 0.843). CONCLUSIONS: We found the association between BRCA1/2 germline mutation status and serum tumor marker levels, and identified discriminative models that combined serum tumor markers with BRCA1/2 mutation status for ovarian cancer detection and patient stratification.

Prevalence and spectrum of AKT1, PIK3CA, PTEN and TP53 somatic mutations in Chinese breast cancer patients.

Breast cancer, one of the most frequently occurring cancers worldwide, is the leading cause of cancer-related death among women. AKT1, PIK3CA, PTEN and TP53 mutations were common observed in breast cancer representing potential clinical biomarkers for cancer classification and treatment. A comprehensive knowledge of AKT1, PIK3CA, PTEN and TP53 mutations in breast cancer was still insufficient in Chinese population. In this study, the complete coding regions and exon-intron boundaries of AKT1, PIK3CA, PTEN and TP53 genes were sequenced in paired breast tumor and normal tissues from 313 Chinese breast cancer patients using microfluidic PCR-based target enrichment and next-generation sequencing technology. Total 120 somatic mutations were identified in 190 of the 313 patients (60.7%), with the mutation frequency of AKT1 as 3.2%, PIK3CA as 36.4%, PTEN as 4.8%, and TP53 as 33.9%. Among these mutations, 1 in PIK3CA (p.I69N), 3 in PTEN (p.K62X, c.635-12_636delTTAACCATGCAGAT and p.N340IfsTer4) and 5 in TP53 (p.Q136AfsTer5, p.K139_P142del, p.Y234dup, p.V274LfsTer31 and p.N310TfsTer35) were novel. Notably, PIK3CA somatic mutations were significantly associated with ER-positive or PR-positive tumors. TP53 somatic mutations were significantly associated with ER-negative, PR-negative, HER2-positive, BRCA1 mutation, Ki67 high expression and basal-like tumors. Our findings provided a comprehensive mutation profiling of AKT1, PIK3CA, PTEN and TP53 genes in Chinese breast cancer patients, which have potential implications in clinical management.

Analysis of BRCA1/2 mutation spectrum and prevalence in unselected Chinese breast cancer patients by next-generation sequencing.

PURPOSE: BRCA1 and BRCA2 (BRCA1/2) are two major high-penetrance breast cancer predisposition genes, mutations in which can lead to high risks and early onset of breast cancer. This study was performed to comprehensively investigate the spectrum and prevalence of BRCA1/2 mutations in unselected Chinese breast cancer patients and evaluate the associations of BRCA1/2 mutations with related clinicopathological characteristics of the tumors. METHODS: By integrating microfluidic PCR-based target enrichment and next-generation sequencing, paired tumor and normal tissues from 313 unselected breast cancer patients were analyzed for both germline and somatic mutations of BRCA1/2 genes in Chinese Han population. RESULTS: Total 5 BRCA1 and 8 BRCA2 deleterious germline mutations were detected in 5 (1.60%) and 12 (3.83%) of the 313 patients, respectively. The entire frequency of deleterious germline mutations of BRCA1/2 was 5.43%. Among them, c.1069A > T and c.3418_3419insTGACTACT in BRCA1, c.8474_8487delCATACCCTATACAG and c.6547delG in BRCA2 were novel. In addition, 32 germline variants of unknown significance in 31 (9.90%) of the 313 patients were identified. We also detected 13 somatic mutations in ten patients (3.19%), including 4 (1.28%) deleterious mutations (c.1575delT, c.2677C > T, c.7024C > T, and c.7672G > T in BRCA2) and 5 novel mutations (c.4728A > G and c.4820T > C in BRCA1; c.2527G > A, c.4069C > G and c.7672G > T in BRCA2). Notably, BRCA1 mutation carriers were significantly younger, and more likely to be ER negative and basal-like breast cancers. CONCLUSIONS: Our study provided a reliable and effective platform for BRCA1/2 genetic testing, and suggested that there was a relatively high prevalence and special spectrum of BRCA1/2 mutations in unselected Chinese breast cancer patients.

Integrated analysis of promoter methylation and expression of telomere related genes in breast cancer.

Telomeres at the ends of eukaryotic chromosomes play a critical role in tumorgenesis. Using microfluidic PCR and next-generation bisulfite sequencing technology, we investigated the promoter methylation of 29 telomere related genes in paired tumor and normal tissues from 184 breast cancer patients. The expression of significantly differentially methylated genes was quantified using qPCR method.We observed that the average methylation level of the 29 telomere related genes was significant higher in tumor than that in normal tissues (P = 4.30E-21). A total of 4 genes (RAD50, RTEL, TERC and TRF1) showed significant hyper-methylation in breast tumor tissues. RAD51D showed significant methylation difference among the four breast cancer subtypes. The methylation of TERC showed significant association with ER status of breast cancer. The expression profiles of the 4 hyper-methylated genes showed significantly reduced expression in tumor tissues. The integration analysis of methylation and expression of these 4 genes showed a good performance in breast cancer prediction (AUC = 0.947).Our results revealed the methylation pattern of telomere related genes in breast cancer and suggested a novel 4-gene panel might be a valuable biomarker for breast cancer diagnosis.

A Comparative Analysis of the Venom Gland Transcriptomes of the Fishing Spiders Dolomedes mizhoanus and Dolomedes sulfurous.

Dolomedes sulfurous and Dolomedes mizhoanus are predaceous arthropods catching and feeding on small fish. They live in the same area and have similar habits. Their venoms exhibit some similarities and differences in biochemical and electrophysiological properties. In the present work, we first performed a transcriptomic analysis by constructing the venom gland cDNA library of D. sulfurous and 127 novel putative toxin sequences were consequently identified, which were classified into eight families. This venom gland transcriptome was then compared with that of D. mizhoanus, which revealed that the putative toxins from both spider venoms might have originated from the same gene ancestors although novel toxins were evolved independently in the two spiders. The putative toxins from both spiders contain 6-12 cysteine residues forming seven cysteine patterns. As revealed by blast search, the two venoms are rich in neurotoxins targeting ion channels with pharmacological and therapeutic significance. This study provides insight into the venoms of two closely related species of spider, which will be of use for future investigations into the structure and function of their toxins.