Inhibition of SIRT7 overcomes sorafenib acquired resistance by suppressing ERK1/2 phosphorylation via the DDX3X-mediated NLRP3 inflammasome in hepatocellular carcinoma.

AIMS: Sirtuin 7 (SIRT7) plays an important role in tumor development, and has been characterized as a potent regulator of cellular stress. However, the effect of SIRT7 on sorafenib acquired resistance remains unclear and a possible anti-tumor mechanism beyond this process in HCC has not been clarified. We examined the therapeutic potential of SIRT7 and determined whether it functions synergistically with sorafenib to overcome chemoresistance. METHODS: Cancer Genome Atlas-liver HCC data and unbiased gene set enrichment analyses were used to identify SIRT7 as a potential effector molecule in sorafenib acquired resistance. Two types of SIRT7 chemical inhibitors were developed to evaluate its therapeutic properties when synergized with sorafenib. Mass spectrometry was performed to discover a direct target of SIRT7, DDX3X, and DDX3X deacetylation levels and protein stability were explored. Moreover, an in vivo xenograft model was used to confirm anti-tumor effect of SIRT7 and DDX3X chemical inhibitors combined with sorafenib. RESULTS: SIRT7 inhibition mediated DDX3X depletion can re-sensitize acquired sorafenib resistance by disrupting NLRP3 inflammasome assembly, finally suppressing hyperactive ERK1/2 signaling in response to NLRP3 inflammasome-mediated IL-1ß inhibition. CONCLUSIONS: SIRT7 is responsible for sorafenib acquired resistance, and its inhibition would be beneficial when combined with sorafenib by suppressing hyperactive pro-cell survival ERK1/2 signaling.

Low value of staging in detecting extraovarian occult metastasis in mucinous borderline ovarian tumors.

OBJECTIVES: Staging procedure in borderline ovarian tumors is a topic of controversy. Upstaging in non-serous borderline ovarian tumors that are confined to the ovary is rare. The aim of this study was to assess the impact of surgical staging on clinical outcomes in mucinous borderline ovarian tumors. METHODS: This was a retrospective study conducted at the Asan Medical Center, Seoul, Korea between January 1990 and December 2015, that included 432 patients with mucinous borderline ovarian tumors and at least 6 months follow-up. These patients were divided into a 'staging group' and 'unstaged group'. The staging group referred to patients who, in addition to hysterectomy and/or adnexal surgery, underwent at least one of the following: cytology, omental biopsy/omentectomy, peritoneal biopsy, lymph node biopsy/lymphadenectomy, or appendectomy. The unstaged group referred to patients who did not undergo any staging procedure but underwent adnexal surgery (cystectomy or oophorectomy). RESULTS: Median patient age was 40 (range 9-87) years. A total of 367 patients (85%) underwent a staging procedure (staging group) and 65 (15.0%) patients did not (unstaged group). Among the staging group, 258, 4, 100, and 5 patients were FIGO stage IA, IB, IC, or II-III, respectively. Overall recurrence was confirmed in 15 patients and median time to recurrence was 13.4 (range 0.4-127.3) months. One patient was in the unstaged group and had borderline recurrence. Fourteen were in the staging group, and 11 of them had borderline and three had invasive recurrence. Extraovarian disease was found at recurrence only in two patients. There was no significant difference in recurrence-free survival (p=0.39) and in overall survival between the staging group and the unstaged group (p=0.40). In total, 16 (4.4%) of 367 patients who underwent a staging procedure were upstaged. CONCLUSION: Staging in mucinous borderline ovarian tumors may be omitted if there is no obvious evidence of gross extraovarian disease.

Identification of a novel SIRT7 inhibitor as anticancer drug candidate.

Sirtuins (SIRT1-7), a class of deacetylases, play major roles in DNA damage repair, aging, and metabolism in yeast and in mammals. SIRT7 is localized in the nucleolus. It regulates cellular processes, including genomic stability, rDNA transcription, and cell proliferation, and plays a role in tumorigenesis. SIRT7 deacetylates its substrates histone H3 (at lysine 18) and p53. p53, a tumor suppressor, induces apoptosis or cell cycle arrest and is stabilized by acetylation. p53 deacetylation at K382 by SIRT7 suppressed cancer cell growth by attenuating p53 activity. Therefore, identification of novel SIRT7 enzyme inhibitors is important. In this study, we found a novel inhibitor of SIRT7 (ID: 97491) that decreased SIRT7 activity in a dose-dependent manner. ID: 97491 induced expression of p53 and its acetylation by inhibited SIRT7. Moreover, ID: 97491 upregulated apoptotic effects through the caspase related proteins and inhibited cancer growth in vivo. The study results suggest that ID: 97491 can be a potential candidate to inhibit the deacetylase activity of SIRT7 and prevent tumor progression by increasing p53 stability through acetylation at K373/382.

Distribution and ecological risk of pharmaceuticals in surface water of the Yeongsan river, Republic of Korea.

This study examined the distribution of pharmaceuticals in Yeongsan River and at point sources (PSs) in the associated water system, and performed a risk assessment based on our findings. The samples included effluents collected from three sewage treatment plants (PS1, PS2, and PS3) and two industrial complexes (PS4 and PS5) as well as surface water collected from seven mainstreams and 11 tributaries of the river. The target pharmaceuticals were acetylsalicylic acid, carbamazepine, clarithromycin, naproxen, sulfamethazine, sulfamethoxazole, sulfathiazole, and trimethoprim, which were detected by liquid chromatography-tandem mass spectrometry. All pharmaceuticals except acetylsalicylic acid and sulfathiazole were found in PS1, PS2, and PS3 samples, whereas acetylsalicylic acid, carbamazepine, sulfamethazine, and sulfamethoxazole were found in PS4, most of the pharmaceuticals were not present in PS5. The rank order of pharmaceutical concentration in surface water was carbamazepine (97.2%, 0.2067 µg/L) > sulfamethoxazole (88.9%, 0.1132 µg/L) > naproxen (51.4%, 0.0516 µg/L) > clarithromycin (43.1%, 0.0427 µg/L). The distribution of pharmaceuticals in the Yeongsan River at PSs and non-PSs differed, and higher concentrations of human pharmaceuticals were detected in upstream and midstream areas whereas higher concentrations of animal pharmaceuticals were found downstream. Hazard quotients (HQs) evaluated at each sites based on mean concentration and 95% upper confidence limits (95% UCLs) were all less than one, indicating a low risk of toxicity. The findings of this study are expected to be useful for risk assessment of aquatic ecosystems.

Quantitative Proteomic Analysis of Changes Related to Age and Calorie Restriction in Rat Liver Tissue.

Calorie restriction (CR) is the most frequently studied mechanism for increasing longevity, protecting against stress, and delaying age-associated diseases. Most studies have initiated CR in young animals to determine the protective effects against aging. Although aging phenomena are well-documented, the molecular mechanisms of aging and CR remain unclear. In this study, we observe changes in hepatic proteins upon age-related and diet-restricted changes in the rat liver using quantitative proteomics. Quantitative proteomes are measured using tandem mass tag labeling followed by LC-MS/MS. We compare protein levels in livers from young (6 months old) and old (25 months old) rats with 40% calorie-restricted (YCR and OCR, respectively) or ad libitum diets. In total, 44 279 peptides and 3134 proteins are identified and 260 differentially expressed proteins are found. Functional enrichment analysis show that these proteins are mainly involved in glucose and fatty acid metabolism-related processes, consistent with the theory that energy metabolism regulation is dependent on age-related and calorie-restricted changes in liver tissue. In addition, proteins mediating inflammation and gluconeogenesis are increased in OCR livers, but not YCR livers. These results show that CR in old rats might not have antiaging benefits because liver inflammation is increased.

Comparison of Laparoscopic and Open Surgery for Patients With Borderline Ovarian Tumors.

OBJECTIVES: The aim of this study was to compare surgical and oncologic outcomes of open and laparoscopic surgery in patients with borderline ovarian tumors (BOTs). MATERIALS AND METHODS: This study included patients with BOTs who underwent open (n = 433) or laparoscopic (n = 210) surgery between 1990 and 2015. Surgical outcomes, perioperative morbidity, and disease-free survival and overall survival were compared. RESULTS: There was no significant difference in age, histologic type of tumor, and laterality of tumor. However, body mass index was slightly higher for the open surgery group (P = 0.046). The open surgery group had a higher serum cancer antigen 125 level (P < 0.001), larger tumor size (P < 0.001), more frequent radical surgery (P = 0.001), higher stage (P = 0.034), and higher incidence of invasive implants (P = 0.035). The operative time (P < 0.001), time interval to return of bowel movement (P < 0.001), and length of postoperative hospital stay (P < 0.001) were significantly shorter and estimated blood loss was significantly less (P < 0.001) in the laparoscopic group. Perioperative complications were documented in 5 (2.4%) patients in the laparoscopic surgery group and 17 (3.9%) in the open surgery group (P = 0.064). Twenty-three (5.3%) patients in the open surgery group and 9 (4.3%) in the laparoscopic surgery group had recurrence (P = 0.902) at a median follow-up of 57 months. The 10-year disease-free survival was 96% and 97% for the open and laparoscopic groups, respectively (P = 0.851), with no significant difference between the groups after adjusting for independent factors (odds ratio, 1.0; 95% confidence interval, 0.4-2.4; P = 0.999). The 10-year overall survival was 99% for both groups, respectively (P = 0.441). CONCLUSIONS: Laparoscopic surgery and open surgery showed similar survival outcomes in BOTs. The surgical outcomes of laparoscopic surgery were more favorable.

Discovery of novel tetrahydroisoquinoline-containing pyrimidines as ALK inhibitors.

Exploration of the two-position side chain of pyrimidine in LDK378 with tetrahydroisoquinolines (THIQs) led to discovery of 8 and 17 as highly potent ALK inhibitors. THIQs 8 and 17 showed encouraging in vitro and in vivo xenograft efficacies, comparable with those of LDK378. Although THIQ analogs (8a-o and 17a-i) prepared were not as active as their parent compounds, both 8 and 17 have significant inhibitory activities against various ALK mutant enzymes including G1202R, indicating that this series of compounds could be further optimized as useful ALK inhibitors overcoming the resistance issues found from crizotinib and LDK378.

Simultaneous determination of seven multiclass veterinary antibiotics in surface water samples in the Republic of Korea using liquid chromatography with tandem mass spectrometry.

A simultaneous determination method using solid-phase extraction and liquid chromatography with tandem mass spectrometry was developed to detect and quantify the presence of seven multiclass veterinary antibiotics (13 compounds in total) in surface water samples, which included the effluents of livestock wastewater and sewage treatment plants, as well as the reservoir drainage areas from dense animal farms. The pH of all water samples was adjusted to 2 or 6 before solid-phase extraction using Oasis HLB cartridges. The developed method was fully validated in terms of linearity, method detection limit, method quantitation limit, accuracy, and precision. The linearity of all tested drugs was good, with R2 determination coefficients ≥ 0.9931. The method detection limits and method quantitation limits were 0.1-74.3 and 0.5-236.6 ng/L, respectively. Accuracy and precision values were 71-120 and 1-17%, respectively. The determination method was successfully applied for monitoring water samples obtained from the Yeongsan River in 2015. The most frequently detected antibiotics were lincomycin (96%), sulfamethazine (90%), sulfamethoxazole (88%), and sulfathiazole (50%); the maximum concentrations of which were 398.9, 1151.3, 533.1, and 307.4 ng/L, respectively. Overall, the greatest numbers and concentrations of detected antibiotics were found in samples from the effluents of livestock wastewater, sewage treatment plants, and reservoir drainage areas. Diverse veterinary antibiotics were present, and their presence was dependent upon the commercial sales and environmental properties of the analytes, the geographical positions of the sampling points, and the origin of the water.

A serum protein profile predictive of the resistance to neoadjuvant chemotherapy in advanced breast cancers.

Prediction of the responses to neoadjuvant chemotherapy (NACT) can improve the treatment of patients with advanced breast cancer. Genes and proteins predictive of chemoresistance have been extensively studied in breast cancer tissues. However, noninvasive serum biomarkers capable of such prediction have been rarely exploited. Here, we performed profiling of N-glycosylated proteins in serum from fifteen advanced breast cancer patients (ten patients sensitive to and five patients resistant to NACT) to discover serum biomarkers of chemoresistance using a label-free liquid chromatography-tandem MS method. By performing a series of statistical analyses of the proteomic data, we selected thirteen biomarker candidates and tested their differential serum levels by Western blotting in 13 independent samples (eight patients sensitive to and five patients resistant to NACT). Among the candidates, we then selected the final set of six potential serum biomarkers (AHSG, APOB, C3, C9, CP, and ORM1) whose differential expression was confirmed in the independent samples. Finally, we demonstrated that a multivariate classification model using the six proteins could predict responses to NACT and further predict relapse-free survival of patients. In summary, global N-glycoproteome profile in serum revealed a protein pattern predictive of the responses to NACT, which can be further validated in large clinical studies.

A peptide of PilZ domain-containing protein controls wastewater-treatment-membrane biofouling by inducing bacterial attachment.

Membrane-based wastewater reclamation is used to mitigate water scarcity; however, irreversible biofouling is an elusive problem that hinders the efficiency of a forward-osmosis (FO) membrane-based process, and the protein responsible for fouling is unknown. Herein, we identified fouling proteins by analyzing the microbiome and proteome of wastewater extracellular polymeric substances responsible for strong irreversible FO-membrane fouling. The IGLSSLPR peptide of a PilZ domain-containing protein was found to recruit bacterial attachment when immobilized on the membrane surface while suppressing it when dissolved, in a similar manner to the Arg-Gly-Asp (RGD) peptide in mammalian cell cultures. Bacteria adhere to IGLSSLPR and poly-l-lysine-coated membranes with similar energies and exhibit water fluxes that decline similarly, which is ascribable to interaction as strong as electrostatic interactions in the peptide-coated membranes. We conclude that IGLSSLPR is the key domain responsible for membrane fouling and can be used to develop antifouling technology against bacteria, which is similar to the current usage of RGD peptide in mammalian cell cultures.

Fully automated multifunctional ultrahigh pressure liquid chromatography system for advanced proteome analyses.

A multifunctional liquid chromatography system that performs 1-dimensional, 2-dimensional (strong cation exchange/reverse phase liquid chromatography or SCX/RPLC) separations and online phosphopeptide enrichment using a single binary nanoflow pump has been developed. With a simple operation of a function selection valve equipped with a SCX column and a TiO2 (titanium dioxide) column, a fully automated selection of three different experiment modes was achieved. Because the current system uses essentially the same solvent flow paths, the same trap column, and the same separation column for reverse-phase separation of 1D, 2D, and online phosphopeptides enrichment experiments, the elution time information obtained from these experiments is in excellent agreement, which facilitates correlating peptide information from different experiments. The final reverse-phase separation of the three experiments is completely decoupled from all of the function selection processes; thereby salts or acids from SCX or TiO2 column do not affect the efficiency of the reverse-phase separation.

Effects of maternal and placental inflammation on retinopathy of prematurity.

PURPOSE: To identify maternal and placental risk factors for the occurrence and progression of retinopathy of prematurity (ROP). METHODS: This was a retrospective cohort study. The study cohort consisted of 246 infants with gestational age ≤ 32 weeks, with histologic examinations of their placentas. Medical records of eligible preterm infants were retrospectively reviewed. A regression model was constructed with control for known or potential factors associated with ROP. Occurrences of ROP, severe ROP (≥ stage 3), and clinically significant ROP requiring laser treatment were assessed. RESULTS: ROP was diagnosed in 82 of 246 infants (33.3%), including 49 with mild ROP and 33 with severe ROP. Laser treatment was performed on 27 infants (11%: 27/246). Multivariate regression analysis indicated clinical chorioamnionitis and elevated maternal WBC count on admission to be associated with ROP occurrence [odds ratio (OR) = 4.370, P = 0.046; and OR = 1.104 per 1,000 cells/mm(3) incremental increase, P = 0.019, respectively], while the use of tocolytics was associated with reduced occurrence of ROP (OR = 0.278, P = 0.006). Elevated maternal WBC count on admission was also independently associated with ROP progression requiring laser treatment (OR = 1.171 per 1,000 cells/mm(3) incremental increase, P = 0.026). However, neither histologic chorioamnionitis nor funisitis was associated with the occurrence or progression of ROP. CONCLUSIONS: Clinical chorioamnionitis and elevated maternal WBC count, but not histologic chorioamnionitis, were significantly and independently associated with ROP. These findings support the hypothesis that maternal systemic inflammation may play a role in the pathogenesis of ROP.

Self-obtained vaginal samples for HPV DNA testing to detect HPV-related cervical disease.

OBJECTIVE: To investigate if a self-obtained vaginal sample (SOVAS) contains sufficient DNA for a human papillomavirus (HPV) test and if the results are comparable to those obtained via cervical samples (CS) collected by a physician. METHODS: One hundred and fifty-one women who had abnormal cervical smears or who were HPV-positive were enrolled. Self-sampling was done after reading instructions and watching a 2-min-long video, whereas CS was obtained with a cervical cytobrush during a gynecologic examination. RESULTS: A multiplex real-time polymerase chain reaction-based assay detected the prevalence of any type of HPV to be 67.5% in the SOVAS and 57.4% in the CS, and that of high-risk (HR-) HPV to be 58.7% in the SOVAS and 48.6% in the CS. The sensitivity of detection of HR-HPV in the SOVAS was 100% (95% confidence interval [CI] -0.09 to 0.32) for high-grade squamous intraepithelial lesion, 78% (95% CI -0.09 to 0.13) for atypical squamous cells of undetermined significance or worse, and 95% (95% CI -0.01 to 0.25) for low-grade squamous intraepithelial lesion or worse, which was statistically within the non-inferiority margin compared with that of CS. CONCLUSION: Our study shows that the collection of a SOVAS is feasible and it is comparable to a CS for HPV DNA testing. Future studies are required to investigate the feasibility and cost-effectiveness of a mail-delivered SOVAS for cervical cancer screening.

RUNX3 methylation drives hypoxia-induced cell proliferation and antiapoptosis in early tumorigenesis.

Inactivation of tumor suppressor Runt-related transcription factor 3 (RUNX3) plays an important role during early tumorigenesis. However, posttranslational modifications (PTM)-based mechanism for the inactivation of RUNX3 under hypoxia is still not fully understood. Here, we demonstrate a mechanism that G9a, lysine-specific methyltransferase (KMT), modulates RUNX3 through PTM under hypoxia. Hypoxia significantly increased G9a protein level and G9a interacted with RUNX3 Runt domain, which led to increased methylation of RUNX3 at K129 and K171. This methylation inactivated transactivation activity of RUNX3 by reducing interactions with CBFß and p300 cofactors, as well as reducing acetylation of RUNX3 by p300, which is involved in nucleocytoplasmic transport by importin-α1. G9a-mediated methylation of RUNX3 under hypoxia promotes cancer cell proliferation by increasing cell cycle or cell division, while suppresses immune response and apoptosis, thereby promoting tumor growth during early tumorigenesis. Our results demonstrate the molecular mechanism of RUNX3 inactivation by G9a-mediated methylation for cell proliferation and antiapoptosis under hypoxia, which can be a therapeutic or preventive target to control tumor growth during early tumorigenesis.

Integrated post-experiment monoisotopic mass refinement: an integrated approach to accurately assign monoisotopic precursor masses to tandem mass spectrometric data.

Accurate assignment of monoisotopic precursor masses to tandem mass spectrometric (MS/MS) data is a fundamental and critically important step for successful peptide identifications in mass spectrometry based proteomics. Here we describe an integrated approach that combines three previously reported methods of treating MS/MS data for precursor mass refinement. This combined method, "integrated post-experiment monoisotopic mass refinement" (iPE-MMR), integrates steps (1) generation of refined MS/MS data by DeconMSn; (2) additional refinement of the resultant MS/MS data by a modified version of PE-MMR; and (3) elimination of systematic errors of precursor masses using DtaRefinery. iPE-MMR is the first method that utilizes all MS information from multiple MS scans of a precursor ion including multiple charge states, in an MS scan, to determine precursor mass. With the combination of these methods, iPE-MMR increases sensitivity in peptide identification and provides increased accuracy when applied to complex high-throughput proteomics data.

Postexperiment monoisotopic mass filtering and refinement (PE-MMR) of tandem mass spectrometric data increases accuracy of peptide identification in LC/MS/MS.

Methods for treating MS/MS data to achieve accurate peptide identification are currently the subject of much research activity. In this study we describe a new method for filtering MS/MS data and refining precursor masses that provides highly accurate analyses of massive sets of proteomics data. This method, coined "postexperiment monoisotopic mass filtering and refinement" (PE-MMR), consists of several data processing steps: 1) generation of lists of all monoisotopic masses observed in a whole LC/MS experiment, 2) clusterization of monoisotopic masses of a peptide into unique mass classes (UMCs) based on their masses and LC elution times, 3) matching the precursor masses of the MS/MS data to a representative mass of a UMC, and 4) filtration of the MS/MS data based on the presence of corresponding monoisotopic masses and refinement of the precursor ion masses by the UMC mass. PE-MMR increases the throughput of proteomics data analysis, by efficiently removing "garbage" MS/MS data prior to database searching, and improves the mass measurement accuracies (i.e. 0.05 +/- 1.49 ppm for yeast data (from 4.46 +/- 2.81 ppm) and 0.03 +/- 3.41 ppm for glycopeptide data (from 4.8 +/- 7.4 ppm)) for an increased number of identified peptides. In proteomics analyses of glycopeptide-enriched samples, PE-MMR processing greatly reduces the degree of false glycopeptide identification by correctly assigning the monoisotopic masses for the precursor ions prior to database searching. By applying this technique to analyses of proteome samples of varying complexities, we demonstrate herein that PE-MMR is an effective and accurate method for treating massive sets of proteomics data.

An extremely rare elderly case of proximal epithelioid sarcoma of the vulva: case report with a review of literatures.

We experienced an extremely rare case of proximal epithelioid sarcoma (PES) of the vulva in a 77-year-old woman. After history taking and physical examination, the patient was tentatively diagnosed as having Bartholin's cyst in the right labium. Based on histopathological and immunohistochemical (IHC) findings, however, a final diagnosis of PES of the vulva was made. After receiving CyberKnife treatment, the patient survived but with recurrent episodes and poor prognosis. In conclusion, our case indicates that patients with PES of the vulva should be appropriately managed with radiotherapy after a differential diagnosis based on histopathological and IHC findings.

OutlierD: an R package for outlier detection using quantile regression on mass spectrometry data.

UNLABELLED: It is important to preprocess high-throughput data generated from mass spectrometry experiments in order to obtain a successful proteomics analysis. Outlier detection is an important preprocessing step. A naive outlier detection approach may miss many true outliers and instead select many non-outliers because of the heterogeneity of the variability observed commonly in high-throughput data. Because of this issue, we developed a outlier detection software program accounting for the heterogeneous variability by utilizing linear, non-linear and non-parametric quantile regression techniques. Our program was developed using the R computer language. As a consequence, it can be used interactively and conveniently in the R environment. AVAILABILITY: An R package, OutlierD, is available at the Bioconductor project at http://www.bioconductor.org

Isotopic peak intensity ratio based algorithm for determination of isotopic clusters and monoisotopic masses of polypeptides from high-resolution mass spectrometric data.

Determining isotopic clusters and their monoisotopic masses is a first step in interpreting complex mass spectra generated by high-resolution mass spectrometers. We propose a mathematical model for isotopic distributions of polypeptides and an effective interpretation algorithm. Our model uses two types of ratios: intensity ratio of two adjacent peaks and intensity ratio product of three adjacent peaks in an isotopic distribution. These ratios can be approximated as simple functions of a polypeptide mass, the values of which fall within certain ranges, depending on the polypeptide mass. Given a spectrum as a peak list, our algorithm first finds all isotopic clusters consisting of two or more peaks. Then, it scores clusters using the ranges of ratio functions and computes the monoisotopic masses of the identified clusters. Our method was applied to high-resolution mass spectra obtained from a Fourier transform ion cyclotron resonance (FTICR) mass spectrometer coupled to reverse-phase liquid chromatography (RPLC). For polypeptides whose amino acid sequences were identified by tandem mass spectrometry (MS/MS), we applied both THRASH-based software implementations and our method. Our method was observed to find more masses of known peptides when the numbers of the total clusters identified by both methods were fixed. Experimental results show that our method performed better for isotopic mass clusters of weak intensity where the isotopic distributions deviate significantly from their theoretical distributions. Also, it correctly identified some isotopic clusters that were not found by THRASH-based implementations, especially those for which THRASH gave 1 Da mismatches. Another advantage of our method is that it is very fast, much faster than THRASH that calculates the least-squares fit.

Carassius auratus-originated recombinant histone H1 C-terminal peptide as gene delivery material.

The effective delivery of exogenous genes into eukaryotic cells is important for fundamental and biotechnological research. Protein-based gene delivery including histone proteins has recently emerged as a powerful technique for non-viral DNA transfer. Histones are DNA-binding proteins that function in DNA packaging and protection. In particular, histone H1 is largely responsible for the stabilization of higher-order chromatin structures. Several studies have examined the use of full-length histone H1-mediated gene transfer, and a few studies have investigated the use of C-terminal histone H1 fragments as gene-transfer materials. Previously, we cloned a novel histone H1 cDNA from the goldfish Carassius auratus and found that a recombinant histone H1 C-terminal short peptide (H1C) of 61 amino acids has comparable DNA binding and protection functions as full-length histone H1. In the present work, we successfully expressed and purified soluble recombinant H1C in an Escherichia coli expression system using a hexahistidine tag fusion strategy and providing tRNAs for rare codons. We confirmed its DNA-binding ability and found that this H1C peptide had similar or higher transfection efficiency in mammalian cells (human 293T and mouse NIH/3T3) than the widely used agent lipofectamine. Therefore, we suggest that this novel goldfish-derived recombinant histone H1 C-terminal short peptide could be used as a peptide-based gene-transfer mediator.