As the most effective and popular gene-editing tool, clustered regularly interspaced short palindromic repeats (CRISPR) technology has produced a revolution in biological fundamental research, medicine and biotechnology. In this review, we describe the history of the CRISPR-CRISPR-associated protein (Cas) systems, the tools of CRISPR-Cas9, CRISPR-FnCas9/RCas9, CRISPR-Cas13 and CRISPR-Cas12a, and then some comments we need to think about.
ObjectiveTo systematically review the relationship between the expression of CXCL12/CXCR4 and pancreatic cancer.MethodsPubMed, EMbase, The Cochrane Library, Wiley Online Library, CNKI, VIP, WanFang Data and CBM databases were electronically searched to collect case-control studies on CXCL12/CXCR4 expression in pancreatic cancer from inception to February 1st 2020. Two reviewers independently screened literature, extracted data and assessed the risk of bias of included studies; then, meta-analysis was performed by using RevMan 5.3 software.ResultsA total of 21 case-control studies involving 1 677 cases and 1 690 controls were included. The results of meta-analysis showed that the expression of CXCR4 in pancreatic cancer tissue was higher than normal tissue (OR=21.40, 95%CI 5.70 to 80.31, P<0.01), in carcinoma of head of pancreas been higher than carcinoma of pancreatic body and tail, (OR=1.58, 95%CI 1.02 to 2.44, P=0.04), in pancreatic cancer with lymph node metastasis been higher than without lymph node metastasis (OR=3.14, 95%CI 1.98 to 4.99, P<0.01), in pancreatic cancer with high TNM stages (Ⅲ, Ⅳ) been higher than low TNM stages (Ⅰ, Ⅱ) (OR=3.67, 95%CI 1.98 to 6.81, P<0.01), in pancreatic cancer with distant metastasis been higher than without distant metastasis (OR=3.56, 95%CI 1.71 to 7.39, P<0.01), and in pancreatic cancer with vascular invasion was higher than without vascular invasion (OR=3.22, 95%CI 1.70 to 6.09, P<0.01). The expression of CXCR4 was not statistically correlated with age, gender, pancreatic cancer tissue and paracancerous tissue, pancreatic cancer tissue and paracancerous lymph nodes, differentiation degree. There was no statistical correlation between the expression of CXCL12 and the differentiation degree, and lymph node metastasis.ConclusionsIn pancreatic cancer, the high expression of CXCR4 is related to lymph node metastasis, high TNM stage, distant metastasis, vascular invasion indicate poor prognosis. Due to limited quality and quantity of the included studies, more high quality studies are required to verify above conclusions.
ObjectiveTo compare four different transfection reagents for transfection efficiency of rat heart myoblast cells H9C2, to choose the optimal transfection method.MethodsThe plasmids of enhanced green fluorescent protein (EGFP) gene were transfected as exogenous genes to H9C2 cells from four different transfection regents including FuGENE HD, DNA-In CRISPR, Lipofectamine 3000 and Lipofectamine 2000. Fluorescence intensity was measured by fluorescence microscopy and fluorescence microplate reader to evaluate transfection efficiency. The effects of four transfection reagents on cell viability were measured by Cell Counting Kit-8 (CCK-8) reagents.ResultsTransfection efficiency of Lipofectamine 3000 was the highest (>50%), while that of DNA-In CRISPR was the lowest (<1%). The cytotoxicity of Lipofectamine 3000 was the lowest in the four transfection reagents and the cell viability was 94.55% after 48-hour transfection.ConclusionTransfection regent Lipofectamine 3000 has the relatively high transfection efficiency as well as the lowest cytotoxicity, which is more suitable for use in H9C2 cells by transfection.
Objectives To analyze and assess the status of detection of human immune-deficiency virus (HIV) by PCR, and to find a new screening test of HIV. Methods Using the following keywords "diagnosis tests", "AIDS", "PCR" and "HIV", we searched the Medline and CBM from 1991 to 2001. Then we assess each of diagnosis test according to the international standards. Results 567 articles were searched, in which 53 articles were chosen to assess. In these 53 articles, it was found that 47% applied comparison with Golden Standard, 25% calculated sensitivity, 23% calculated specificity, and 23% calculated predictive value, no likelihood ratio was calculated in these articles. Conclusions It was still a kind of pilot-study to apply PCR to screening detection of HIV. The design methods of study should be improved.
Objective To identify and observe the pathogenic gene variant and clinical phenotype in a family with Leber congenital amaurosis (LCA). MethodsA retrospective clinical study. Two patients and four family members from one LCA family (type 7), diagnosed via genetic testing at the First Affiliated Hospital of Xi'an Jiaotong University in January 2024 were included. Detailed patient and family histories were collected. All patients underwent examinations including best-corrected visual acuity (BCVA), intraocular pressure, color fundus photography, fundus autofluorescence (FAF), flash visual evoked potential (F-VEP), full-field electroretinography (ff-ERG), and optical coherence tomography (OCT). Family members underwent BCVA and color fundus photography examinations. Peripheral venous blood (5 ml) was collected from the patients and the four family members for genomic DNA extraction. High-throughput sequencing was used to screen for pathogenic gene variants. Identified variants were verified by Sanger sequencing. All variants were classified according to the American College of Medical Genetics and Genomics (ACMG) guidelines. Bioinformatics software including Mutation Taster, Polyphen-2, PROVEAN, and REVEL was used to analyze the pathogenicity of the variants. Results The proband (Ⅱ-2), a 14-year-old female, was born to consanguineous parents (first cousins). Her BCVA was 0.1 in both eyes; intraocular pressure was normal; the anterior segments showed no significant abnormalities. Color fundus photography showed waxy optic discs and a "coin-shaped," "salt-and-pepper" appearance in the retina. FAF revealed large areas of hypoautofluorescence in the macular region. OCT showed shallowing or disappearance of the foveal, disorganized retinal layers, and absence of the ellipsoid zone. F-VEP showed recordable P2 waves with no significant delay in peak time but slightly reduced amplitude. ff-ERG showed significantly reduced or non-detectable amplitudes of the scotopic and photopic a- and b-waves. The proband's elder sister (Ⅱ-1) had similar BCVA and fundus findings. The proband's parents (Ⅰ-1, Ⅰ-2), younger brother (Ⅱ-3), and younger sister (Ⅱ-4) showed no significant ocular phenotypic abnormalities. Genetic testing revealed that the proband and her elder sister were homozygous for the CRX gene variant c.122G>A:p.Arg41Gln. The proband's father, mother, and younger brother were heterozygous carriers of the same CRX variant; the younger sister showed no variation at this locus. Based on the clinical presentation, ff-ERG, and genetic test results, the final diagnosis was LCA type 7. According to ACMG guidelines, the c.122G>A variant was classified as likely pathogenic. Mutation Taster and Polyphen-2 software predicted the variant to be damaging; the REVEL score was 0.929, indicating a likely pathogenic variant. Conclusions The homozygous CRX gene variant c.122G>A:p.Arg41Gln causes autosomal recessive LCA type 7 in this family. LCA is characterized by early onset and severe visual impairment.
Objective To explore the relationship between the HBsAg positive patients suffering from hepatocellular carcinoma (HCC) and HBV DNA genotype. Methods By using PCR type-specific primers combined with sequencing of genotype, we analyzed the genotype of HBV DNA in the serum of 500 patients with positive HBsAg in our hospital. Among them, 150 cases suffered from HCC. Results Genotype B and C were both predominant genotypes in HBsAg positive patients. But in HCC group, the rate of genotype C was 65.33% （98/150）, which was significantly higher than that in non-HCC group (88/350, 25.14%), while genotype B, in contrast, was 28.67% （43/150） and 68.86% （241/350）， χ2=75.45， Plt;0.05. The distribution of HBV DNA genotype B or genotype C in different gender or different age groups were not statistically significantly different in cases of HCC (Pgt;0.05). Conclusion Genotype C of HBV DNA is more common in patients with HCC, and maybe there is relationship between genotype C and the occurrence of HCC.
Objective To evaluate the effect of neoadjuvant chemotherapy on the expression of CXCR4 in breast cancer and its clinical significance.Methods The clinical data of 59 patients with breast cancer of stage Ⅱ and stage Ⅲ underwent neoadjuvant chemotherapy with paclitaxel plus epirubicin for 3 cycles between April 2005 and March 2009 were retrospectively analyzed. The expression of CXCR4 in the breast cancer tissues before and after neo-adjuvant chemotherapy was examined by immunohistochemistry and its relationship with clinicopathologic factors was analyzed.Results The CXCR4 positive expression was observed in 56 patients with breast cancer (94.9%), but not in corresponding nontumor normal tissues. The expression level of CXCR4 was correlated to lymph nodes metastasis (P=0.019) and breast cancer stage (P=0.040), but it was not correlated to age of patients, tumor size, grade, hormone receptor (ER and PR)， and HER2 status. The expression level of CXCR4 was significantly decreased after neoadjuvant chemotherapy. Decline extent of CXCR4 expression after chemotherapy and CXCR4 expression level were not correlated to the effect of neoadjuvant chemotherapy, while the effect of chemotherapy in patients expressed CXCR4 in cluster distribution was better than that in scattering distribution (P=0.015). Conclusion The decline extent of CXCR4 expression level after paclitaxel combined with epirubicin neoadjuvant chemotherapy is not correlated to the efficacy, but its expressing distribution may be considered as an index to the effect of neoadjuvant chemotherapy.
ObjectiveTo investigate the relationship between genotype and phenotype in children with CRB1 mutated Leber congenital amaurosis (LCA) and early onset retinal dystrophy (EOSRD).MethodsA retrospective clinical study. From January 2013 to December 2019, 10 children with CRB1 mutated LCA/EOSRD were enrolled in the study. The patients were identified as CRB1 mutation by the second generation targeted capture sequencing, Sanger sequencing and the family segregation analysis. All children underwent electroretinogram (ERG) and fundus examination. At the same time, 6 cases were examined by optical coherence tomography (OCT); 1 case was examined by fluorescein fundus angiography (FFA), 7 cases were examined by wide-angle laser scanning ophthalmoscope (UWF SLO).ResultsThere were 6 cases of LCA and 4 cases of EOSRD in 10 patients with CRB1 gene mutations. The average age of first visit was 3.61 years old. The light and dark wave of ERG was flat in 6 cases, and decreased in 4 cases. A total of 19 pathogenic mutations were detected. There were 1 homozygous mutation and 9 compound heterozygous mutations. There were 4, 2 and 1 cases of “copper-coin” like, “salt and pepper” like and “osteocyte” like pigment changes in retina, 1 case of “crystalline pigment” change and 2 cases of macular pigment scar. In 7 cases of UWF SLO examination, different degrees of para-arteriolar pigment epithelium retention (PPRPE) were found in the middle and peripheral fundus. In 6 cases examined by OCT, the outer layer of retina atrophied and the band of ellipsoid disappeared. Symmetrical cystoid macular edema, splitting cystoid macular degeneration and adhesion of epi-macular membrane to optic disc and macular area were found in 1 case, respectively, the retinal structure was rough and thickened, and the fovea became thinner in 3 cases. In FFA examination, 1 case showed uveitis-like changes with late optic disc fluorescein staining, macular fluorescence accumulation, strong fluorescence diffusing along the blood vessels in each quadrant, peripheral PPRPE of “frost-branch” like strong fluorescence.ConclusionThe relationship between genotype and phenotype of CRB1 mutation is complex, and PPRPE is a common characteristic change.
Objective To investigate the expressions of CXCR4 and β-catenin in pancreatic cancer, explore the relationship between them, and explore the possible biomarkers about invasion and metastasis of pancreatic cancer. Methods Forty-eight samples of pancreatic cancer and 20 samples of normal pancreas tissues were selected. The expressions of CXCR4 and β-catenin were examined by the immunohistological technique. Spearman, Chi-square， and rank test were used to analyze the relation between the protein expressions and clinical characteristics. Survival analysis was evaluated by Kaplan-Meier product limit method and Log-rank test. Variables were evaluated by Cox proportional hazards analysis. The size of test was 0.05. Results The positive expression rates of CXCR4 and β-catenin in pancreatic cancer tissues were 85.4% (41/48) and 75.0% (36/48), respectively. Co-expression rate of CXCR4 and β-catenin was 70.8% (34/48). There were significant differences between various CXCR4 staining and lymph node metastasis and TNM stage (P=0.012, 0.005, respectively). β-catenin positive expression was associated with lymph node metastasis (P=0.047). However, abnormal β-catenin positive expression could not determine the clinical survival. Kaplan-Meier estimated curves suggested that clinical prognosis was poor for patients with CXCR4 expression. Multivariate analysis showed that CXCR4, late TNM stage, and lymph node metastasis were independent prognostic factors for pancreatic cancer. Conclusions Both CXCR4 and β-catenin abnormally express in pancreatic cancer. CXCR4 may be an important marker for pancreatic cancer progression.