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This study constructed a LHCGR-CRE-luc-HEK293 transgenic cell line according to the activation of the cAMP signaling pathway after recombinant human chorionic gonadotropin binding to the receptor. The biological activity of recombinant human chorionic gonadotropin was assayed using a luciferase assay system. The relative potency of the samples was calculated using four-parameter model. And the method conditions were optimized to validate the specificity, relative accuracy, precision and linearity of the method. The results showed that there was a quantitative potency relationship of human chorinonic gonadotropin (hCG) in the method and it was in accordance with the four-parameter curve. After optimization, the conditions were determined as hCG dilution concentration of 2.5 μg·mL-1, dilution ratio of 1∶4, cell number of 10 000-15 000 cells/well, and induction time of 6 h. The method had good specificity, relative accuracy with relative bias ranging from -8.9% to 3.4%, linear regression equation correlation coefficient of 0.996, intermediate precision geometric coefficient of variation ranging from 3.3% to 15.0%, and linearity range of 50% to 200%. This study successfully established and validated a reporter gene method to detect hCG biological activity, which can be used for hCG biological activity assay and quality control.
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MicroRNA-20a-5p (miR-20a-5p) has been shown to function as a tumor promoter factor in several cancers. However, its role in small cell lung cancer (SCLC) remains unclear. In this study, we have made an attempt to measure the tumor tissue levels of miR-20a-5p in patients with SCLC using quantitative real-time reverse transcription polymerase chain reaction (qRT-PCR). The biological function of miR-20a-5p in SCLC cells was investigated in vitro and in vivo studies, including cell proliferation, migration assays and tumorigenicity in nude mice. Meanwhile?we conducted the luciferase reporter assay to verify the biological relationship between miR-20a-5p and CCNG2. The expression of miR-20a-5p was significantly upregulated in human SCLC compared to that in normal tissues. Kaplan-Meier analysis indicated that patients with high expression of miR-20a-5p are closely related with the shorter survival of SCLC. Further, multivariate analysis showed that miR-20a-5p was an independent prognostic factor. Increasing miR-20a-5p expression promotes the proliferation, migration and invasion of the NCI-H446 cells in vitro and in vivo. Dual-luciferase reporter gene assay demonstrated that miR-20a-5p directly targets CCNG2. These findings suggest that miR-20a-5p levels might be a novel diagnostic and prognostic marker of SCLC. Inhibiting miR-20a-5p could be a promising therapeutic strategy for SCLC.
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The goal of this work was to explore the prospect of standardized application of an in-vitro bioactivity assay for recombinant human follicle-stimulating hormone based on a reporter gene. The relative accuracy, intermediate precision, linearity and applicable range of the method were validated according to the General Rules of Chinese Pharmacopoeia 2020 edition Volume IV (9401). Three laboratories used this method to determine the in-vitro biological activities of six batches of drug product and three batches of drug substance manufactured by two different companies. The consistency of the potency determined by three laboratories, the intra-laboratory precision and inter-laboratory precision were analyzed. The method was optimized during the collaborative validation. The results of method validation meet the requirements of the General Rules of Chinese Pharmacopoeia 2020 edition Volume IV (9401). Aiming to resolve the problems found in the collaborative validation, the medium for cell seeding, the pre-diluted buffer solution of standard and sample, and the means of removing and discarding supernatant after stimulation were optimized. After optimization, there was no significant difference in the bioactivity among the different laboratories (P > 0.05), indicating statistical equivalency. Intra-laboratory and inter-laboratory precision were good and the geometric coefficient of variation (GCV%) were both less than 15%. In conclusion, the reporter gene assay has good intra-laboratory repeatability and inter-laboratory reproducibility and is suitable for analyzing recombinant human follicle-stimulating hormone drug product and drug substance by different manufacturers. It is expected to be used as a standardized method for the determination of the in-vitro bioactivity of such products.
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@#Objective To develop and verify a reporter gene assay(RGA) for the detection of biological activity of human growth hormone(hGH).Methods The biological activity of hGH was evaluated by the expression of luciferase(Luc)activated by hGH binding to hGH receptor(hGHR) on HEK293/GH-Luc cell membrane.The developed detection conditions were as follows:the initial concentration of sample was 1 μg/mL;the cell inoculation amount was(2.45～2.66) × 10~4 cells/well;the sample was of 3-fold serial dilution,with a total of 8 dilutions and the incubation time was 18～24 h.The relative biological activity of the sample was calculated by measuring Luc intensity and comparing it with the national standard by four-parameter fitting.The developed method was verified for specificity,repeatability,intermediate precision,relative accuracy,linear range and durability.Results The excipient components in product and the serum components in culture medium showed no effect on the activity detection results;The geometric coefficient of variation(GCV) of relative titer of one batch of samples in six repeated detections was 6.794%,much lower than 20%.The relative titer GCV detected by two experimenters in different batches of samples at different times were both lower than 20%;The relative deviations of the relative titer determination values of samples at different concentrations were within ±12%,the slope of linear regression equation was 0.982,the linear range was 0.6～1.6 μg/mL,and the coefficient of determination(R~2) was 0.997;The GCV of three batches of stock solutions and one batch of finished products were 4.758%,4.430%,7.294% and 2.771% respectively under the conditions of different cell generation,cell density and sampling location,all of which were less than 20%.Conclusion The developed RGA showed good specificity,repeatability,intermediate precision,relative accuracy,linear range and durability,which met the application requirements and was expected to replace the traditional in vivo biological activity detection methods for the activity evaluation and quality control of hGH.
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T cell immunoglobulin and ITIM domain (TIGIT) is a novel immune checkpoint that has been considered as a target in cancer immunotherapy. Current available bioassays for measuring the biological activity of therapeutic antibodies targeting TIGIT are restricted to mechanistic investigations because donor primary T cells are highly variable. Here, we designed a reporter gene assay comprising two cell lines, namely, CHO-CD112-CD3 scFv, which stably expresses CD112 (PVRL2, nectin-2) and a membrane-bound anti-CD3 single-chain fragment variable (scFv) as the target cell, and Jurkat-NFAT-TIGIT, which stably expresses TIGIT as well as the nuclear factor of activated T-cells (NFAT) response element-controlled luciferase gene, as the effector cell. The anti-CD3 scFv situated on the target cells activates Jurkat-NFAT-TIGIT cells through binding and crosslinking CD3 molecules of the effector cell, whereas interactions between CD112 and TIGIT prevent activation. The presence of anti-TIGIT mAbs disrupts their interaction, which in turn reverses the inactivation and luciferase expression. Optimization and validation studies have demonstrated that this assay is superior in terms of specificity, accuracy, linearity, and precision. In summary, this reliable and effective reporter gene assay may potentially be utilized in lot release control, stability assays, screening, and development of novel TIGIT-targeted therapeutic antibodies.
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A collaborative inter-laboratory validation was carried out using a reporter gene assay to measure the bioactivity of anti-PD-1 monoclonal antibody, in order to study the applicability and transferability of the method. In this study, two collaborative schemes were designed to measure the precision, linearity and accuracy of the method. The results showed that the 95% confidence interval (CI) of the intra-assay precision was (1.72-16.89) %, inter-assay precision was (2.63-17.67) %, inter-laboratory precision was (9.00-14.26) %, all linear correlation coefficients were greater than 0.99, and the 95% CI for the accuracy at different potency levels was (91.83-104.40) % at 50%, (90.40-101.40) % at 75%, (94.71-105.60) % at 100%, (94.00-102.00) % at 125%, and (96.73-104.30) % at 150%. The collaborative validation results proved that the reporter gene assay for the bioactivity determination of anti-PD-1 monoclonal antibody has good precision, linearity and accuracy, and could be applied to the release and stability analysis of anti-PD-1 monoclonal antibodies in different laboratories.
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Objective: To study the effect of nuclear factor erythroid-2-related factor 2(Nrf2) and the downstream gene grainyhead-like 2(GRHL2) on epithelial ovarian cancer cell lines and the interaction of Nrf2 and GRHL2. Methods: We conducted ChlP-PCR assay to test the binding of Nrf2 with six candidate genes including GRHL2. Furthermore, we proved whether Nrf2 could bind with the GRHL2 promoter and transcriptionally activate the GRHL2 gene or not. Moreover, if the overexpression and knockdown of Nrf2 could increase and decrease the GRHL2 protein respectively. Results: We discovered that fallopian tube epithelial cells taken from epithelial ovarian cancer patients and ovarian cancer cell lines highly expressed the Nrf2 and GRHL2 at mRNA level. The overexpression and knockdown of Nrf2 could increase and decrease the cells activity, respectively. However, the knockdown of GRHL2 could inhibit the influence of Nrf2 overexpression. Conclusion: Nrf2 promotes the activity of epithelial ovarian cancer cells via modulating the GRHL2 gene transcriptionally.
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OBJECTIVE: To establish the quality control system for the recombinant human GLP-1 analogue fusion protein. METHODS: The potency of the fusion protein was determined by luciferase reporter gene assay. The purity was analyzed by non-reduced SDS-PAGE and SEC-HPLC respectively. RP-HPLC was used for the peptide mapping. ELISA was used to analyze the identification of the final products. The molecular mass and peptide mass spectra were analyzed by LC-ESI-MS technique. Other control tests were performed according to the requirements in the Chinese Pharmacopoeia (Volume III, 2010 edition). RESULTS: Control tests were performed on three different lots of bulks and final products of recombinant GLP-1 analog fusion protein by the developed methods. The results showed that all the indexes met the requirements in the Guideline for Quality Control of Recombinant DNA Products for Human Use and Chinese Pharmacopoeia (Volume III, 2010 edition). The molecular weight of the recombinant human GLP-1 analogue fusion protein was 71 361.0, which was in conformity with the theoretical value. CONCLUSION: The developed methods and standard may assure the safety, effectiveness, and controllability of the recombinant human GLP-1 analogue fusion protein, which might be used for the routine quality control of products of the same kind.
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Aim To study the activation of Nrf2 in-duced by baicalein ( BAI ) , and its protection against carbon tetrachloride ( CCl4 ) , ethanol and acetamino-phen ( APAP )-induced hepatotoxicity. Methods A reporter gene assay was conducted in human normal liver L-02 cells to detect the activation of transcription factor Nrf2 induced by baicalein. APAP ( 10 mmol · L-1 ) , CCl4 (10 mmol·L-1 ) and Ethanol (100 mmol · L-1 ) were used to induce hepatotoxicity in L-02 cells. After the pre-incubation with Baicalein (0, 1, 10, 25, 50, 100 μmol·L-1 ) for 15 min, cells were administrated with or without those above hepatotoxins. 48 h later, cell viability was detected by 3-(4, 5-dim-ethylthiazol-2-yl ) 2 , 5-diphenyltetrazolium bromide (MTT) method. Results Baicalein (25, 50 μmol· L-1 ) induced the activation of Nrf2 ( P <0. 01 , P <0. 05) in the reporter gene assay. As compared with control, three hepatotoxins ( APAP, CCl4 , Ethanol ) all decreased cell viability ( P<0. 01 ) , and baicalein significantly reversed such decreases in a concentra-tion-dependent manner ( P<0. 01 ) . Conclusion Ba-icalein can induce the activation of transcription factor Nrf2 , which is probably one of the mechanisms con-tributing to the protection of baicalein against hepato-toxins (APAP, CCl4, Ethanol)-induced hepatotoxici-ty.
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PURPOSE: To identify the polymorphism in the regulatory region of trabecular meshwork inducible glucocorticoid response(TIGR) gene and evaluate the association of it with glaucoma. METHODS: 5'regulatory region of TIGR gene of 101 normal persons and 91 unrelated glaucoma patients were analyzed by DNA sequencing and restriction enzyme digestion. To know the possible effects of the polymorphism on the transcription rate of TIGR gene, electrophoretic mobility shift assay and luciferase reporter gene assay were performed with cultured cells, and their extracts of trabecular meshwork and ciliary body in which the gene was expressed. RESULTS: Of the 480 bp examined, G to A transition(G-241A) located at 241 bp upstream from transcription start site was identified and its frequency of occurrence was proved to be higher in steroid induced glaucoma patients(18.9%) compared with that in normal population(8.9%), POAG(8.3%) and normal tension glaucoma patients(6.7%, P<0.05). In mobility shift assay, the G-241A probe was proved to have affinity to some DNA-binding proteins and its affinity was revealed to be two times stronger than that of normal sequence. The luciferase activities, however, were observed to be similar in cells transfected with vectors having normal promoter sequence or G-241A containing one. CONCLUSION: The result suggest that G-241A itself is not a cause of steroid-induced glaucoma but is in linkage disequilibrium with the actual causes of the disease.