Prokaryotical expression of structural and non-structural proteins of hepatitis G virus

AIM: To study the epitope distribution of hepatitis G virus (HGV) and to seek for the potential recombinant antigens for the development of HGV diagnostic reagents. METHODS: Fourteen clones encompassing HGV gene fragments from core to NS3 and NS5 were constructed using prokaryotic expression vector pRSET and (or) pGEX, and expressed in E.coli. Western blotting and ELISA were used to detect the immunoreactivity of these recombinant proteins. RESULTS: One clone with HGV fragment from core to E1 (G1), one from E2 (G31), three from NS3 (G6, G61, G7), one from NS5B (G821) and one chimeric fragment from NS3 and NS5B (G61-821) could be expressed well and showed obvious immunoreactivity by Western blotting. One clone with HGV framment from NS5B (G82) was also well expressed, but could not show immunoreactivity by Western blotting. No obvious expression was found in the other six clones. All the expressed recombinant proteins were in inclusion body form, except the protein G61 which could be expressed in soluble form. Further purified recombinant proteins G1, G31, G61, G821 and G61-821 were detected in indirected ELISA as coating antigen respectively. Only recombinant G1 could still show immunoreactivity, and the other four recombinant proteins failed to react to the HGV antibody positive sera. Western blotting results indicated that the immunoactivity of these four recombinant proteins were lost during purification. CONCLUSION: Core to E1, E2, NS3 and NS5 fragment of HGV contain antigenic epitopes, which could be produced in prokaryotically expressed recombinant proteins. A high-yield recombinant protein (G1) located in HGV core to E1 could remain its epitope after purification, which showed the potential that G1 could be used as a coating antigen to develop an ELISA kit for HGV specific antibody diagnosis.

Roles of HIV-1 auxiliary proteins in viral pathogenesis and host-pathogen interactions

Active host-pathogen interactions take place during infection of human immunodeficiency virus type 1 (HIV-1). Outcomes of these interactions determine the efficiency of viral infection and subsequent disease progression. HIV- infected cells respond to viral invasion with various defensive strategies such as innate, cellular and humoral immune antiviral mechanisms. On the other hand, the virus has also developed various offensive tactics to suppress these host cellular responses. Among many of the viral offensive strategies, HIV-1 viral auxiliary proteins (Tat, Rev, Nef, Vif, Vpr and Vpu) play important roles in the host-pathogen interaction and thus have significant impacts on the outcome of HIV infection. One of the best examples is the interaction of Vif with a host cytidine deaminase APOBEC3G. Although specific roles of other auxiliary proteins are not as well described as Vif-APOBEC3G interaction, it is the goal of this brief review to summarize some of the preliminary findings with the hope to stimulate further discussion and investiga- tion in this exhilarating area of research.

The Nucleocytoplasmic Transport of Viral Proteins

Molecules can enter the nucleus by passive diffusion or active transport mechanisms, depending on their size. Small molecules up to size of 50-60 kDa or less than 10 nm in diameter can diffuse passively through the nuclear pore complex （NPC）, while most proteins are transported by energy driven transport mechanisms Active transport of viral proteins is mediated by nuclear localization signals （NLS）, which were first identified in Simian Virus 40 large T antigen and had subsequently been identified in a large number of viral they contain short stretches of lysine or arginine residues. These signals are recognized proteins. Usually by the importin super-family （importin α and β） proteins that mediate the transport across the nuclear envelope through Ran-GTP In contrast, only one class of the leucine-rich nuclear export signal （NES） on viral proteins is known at present. Chromosome region maintenance 1 （CRM1） protein mediates nuclear export of hundreds of viral proteins through the recognition of the leucine-rich NES.

Advances of Studies on the Viral Proteins of PRRSV

Porcine reproductive and respiratory syndrome( PRRS) is one of viral diseases with severe reproductive obstacle of pregnant sows and respiratory tract symptoms and higher mortality of piglets as characteristics,which is caused by porcine reproductive and respiratory syndrome virus( PRRSV). PRRS has brought great threats to swine industry in the world. The advances of studies on the viral proteins of PRRSV were reviewed from the genome,non-structural proteins and structural proteins of PRRSV.

Inhibition of Hepatitis C Virus Genotype 1a Non-Structural Proteins by Small Interference RNA in Human Hepatoma Cell Lines

Hepatitis C virus (HCV) infection and associated liver diseases are still challenging and represent a significant health care burden around the world. Although, the treatment strategies have been improved by the development of novel direct-acting antivirals, but such therapeutic options are still expensive and beyond the financial range of the most infected individuals in developing or even in resource replete countries. It demands an urgent need to search novel and improved alternate treatment strategies to treat the infection. The present study was aimed to develop an in vitro stable cell culture system, persistently expressing HCV genotype 1a non-structural genes and to characterize the inhibitory effects of synthetic siRNAs (short interference RNA) directed against the most conserved regions of nonstructural genes in an in vitro cell culture model. The continuous expression of nonstructural genes for more than 30 days post transfection was detected by reverse transcription polymerase chain reaction (RT-PCR) and Western blot analysis in stable human hepatoma cell line (Huh-7). The gene expression studies revealed significantly reduced gene expression of HCV nonstructural genes (i.e., NS2, NS4A and NS5A) both at mRNA and protein levels when treated against genome specific synthetic siRNAs in stable cell lines (51%, 47% and 54% respectively, p < 0.05). Similarly, a vivid decrease in HCV viral titer was exhibited by synthetic siRNAs in an in vitro viral replicate cell culture model (58%, 48% and 50%, respectively, p < 0.05) determined by quantitative Real-Time PCR (qPCR). Our data indicate that siRNA mediated gene silencing may be considered a promising alternate treatment strategy against HCV in combination with other effective therapeutic regimens in future.

Preparation and application of monoclonal antibodies against hepatitis C virus nonstructural proteins

AIM To prepare hybridoma cell lines which secrete anti HCV recombinant NS3 and NS5 proteins′ monoclonal antibodies, and to evaluate their usage in the study of the distribution of HCV NS3 and NS5 antigen in liver tissues. METHODS The hybridoma cell lines were raised using the spleen cells of BALB/C mouse immunized with recombinant NS3 and NS5 proteins according to the conventional protocols. The antibody secreting cells were screened using solid phase ELISA and cloned by limited dilution method. In order to determine the specificity of these hybridoma cell lines, the culture supernatant of these cells was western blot assayed with expression and nonexpresion E. coli and ELISA with other antigens, including HCV core and NS3 and HBsAg. Immunohistochemistry of 51 cases paraffin embedded liver tissues was performed to determine the distribution of HCV NS5 antigen as well as NS3 antigen in liver tissues. RESULTS Eight hybridoma cell lines secreting monoclonal antibodies against HCV NS3 and NS5 proteins were raised. They are named 2B6, 2F3, 3D8, 3D9, 8B2, 6F11, 4C6 and 7D9. Among them only 2B6 against NS3 protein can react with the polypipetides of C7 that is another recombinant polypipetides of NS3 gene. Others have no reaction with HCV core and HBsAg of HBV, and there is no cross reaction between NS3Ag and anti NS5Ag McAb and between NS5Ag and anti NS3 McAb. The immunohistochemistry results indicate that no HCV antigen was detected in the specimens of HBV infection in 20 cases. In 31 HCV infected specimens the positive rate of NS3Ag and NS5Ag are 51 6% (16/31) and 54 9% (17/31), respectively. There were six pure HCV infected specimens in these 31 specimens and half of them were HCV NS3Ag and NS5Ag positive. In the co infection of HBV and HCV group the positive rate of NS3Ag and NS5Ag were 52% (13/25) and 56% (14/25), respectively, almost the same with that of pure HCV infected group. The positive rates of HCV antigens were 70 6% (12/17) and 76 5% (13/17) in CAC patients. CONCLUSION The monoclonal antibodies we prepared are specific to the recombinant HCV NS3 and NS5 proteins and can be used in the clinical immunohistochemistry diagnosis.

Suppression of Breast Cancer Proliferation and Induction of Apoptosis via AKT and ERK1/2 Signal Transduction Pathways by Synthetic Polypeptide Derived from Viral Macrophage Inflammatory Protein Ⅱ

SDF-1α,a ligand for the chemokine receptor CXCR4,is well known for mediating the migration of breast cancer cells.In a previous study we demonstrated that a synthetic 21-mer peptide antagonist of CXCR4（NT21MP） derived from the viral macrophage inflammatory protein Ⅱ could antagonize tumor growth in vivo by inhibiting cellular proliferation and inducing apoptosis in breast cancer cells.However,the role of SDF-1α in the signaling pathways underlying the proliferation of human breast cancer cells and associated signaling pathways and inhibiting signal pathways of NT21MP remained unclear.The present study investigated the mechanism of NT21MP on anti-tumor in breast cancer in vitro.The effect of NT21MP on the viability of cells was determined by the MTT assay.Annexin V-FITC and PI staining was performed to detect early stage apoptosisin SKBR3 cells treated with SDF-1α and AMD3100 or NT21MP.Western blotting techniques were used to assay the composition of phosphoproteomics and total proteins present in the SKBR3 breast cancer cells.RT-PCR and Western blotting technique were used to detect the effect of NT21MP and AMD3100 on Bcl-2 and Bax expression.The results indicated that SDF-1α prevented apoptosis and promoted the proliferation of SKBR3 human breast cancer cells.As compared with untreated SKBR3 cells,Treatment with SDF-1α significantly increased cell viability,and NT21MP abolished the protective effects of SDF-1α dose-dependently（P0.05）.There was a significant decrease in the percentage of apoptotic cells after SDF-1α treatment as compared with control group（2.7%±0.2% vs.5.7%±0.4%,P0.05）.But pretreatment of SKBR3 cells with NT21MP significantly attenuated the antiapoptotic effects of SDF-1α as compared with SKBR3 cells without NT21MP pretreatment.The proliferative and anti-apoptotic effects of SDF-1α in SKBR3 cells were associated with an increase in AKT and ERK1/2 phosphorylation as well as a decrease in Bax expression and an increase in Bcl-2 expression.These changes in intracellular processes were blocked by NT21MP in a dose-dependent manner（P0.05）.In conclusion,NT21MP efficiently inhibits SDF-1α-induced proliferation and antiapoptosis in SKBR3 cells by reducing the levels of phosphorylated AKT and ERK1/2,as well as decreasing the ratio of expression of Bcl-2 relative to Bax.

Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry

BACKGROUND Hepatitis C virus genotype 3a(HCV G3a)is highly prevalent in Pakistan.Due to the elevated cost of available Food and Drug Administration-approved drugs against HCV,medicinal natural products of potent antiviral activity should be screened for the cost-effective treatment of the disease.Furthermore,from natural products,active compounds against vital HCV proteins like non-structural protein 3(NS3)protease could be identified to prevent viral proliferation in the host.AIM To develop cost-effective HCV genotype 3a NS3 protease inhibitors from citrus fruit extracts.METHODS Full-length NS3 without co-factor non-structural protein 4A(NS4A)and codon optimized NS3 protease in fusion with NS4A were expressed in Escherichia coli.The expressed protein was purified by metal ion affinity chromatography and gel filtration.Citrus fruit extracts were screened using fluorescence resonance energy transfer(FRET)assay against the protease and polyphenols were identified as potential inhibitors using electrospray ionization-mass spectrometry(MS)/MS technique.Among different polyphenols,highly potent compounds were screened using molecular modeling approaches and consequently the most active compound was further evaluated against HCV NS4A-NS3 protease domain using FRET assay.RESULTS NS4A fused with NS3 protease domain gene was overexpressed and the purified protein yield was high in comparison to the lower yield of the full-length NS3 protein.Furthermore,in enzyme kinetic studies,NS4A fused with NS3 protease proved to be functionally active compared to full-length NS3.So it was concluded that co-factor NS4A fusion is essential for the purification of functionally active protease.FRET assay was developed and validated by the half maximal inhibitory concentration(IC50)values of commercially available inhibitors.Screening of citrus fruit extracts against the native purified fused NS4A-NS3 protease domain showed that the grapefruit mesocarp extract exhibits the highest percentage inhibition 91%of protease activity.Among the compounds identified by LCMS analysis,hesperidin showed strong binding affinity with the protease catalytic triad having S-score value of-10.98.CONCLUSION Fused NS4A-NS3 protease is functionally more active,which is effectively inhibited by hesperidin from the grapefruit mesocarp extract with an IC50 value of 23.32μmol/L.

Dengue virus non-structural 1 protein interacts with heterogeneous nuclear ribonucleoprotein H in human monocytic cells

Objective: To study protein-protein interaction between heterogeneous nuclear ribonucleoprotein H(hn RNP H) and Dengue virus(DENV) proteins. Methods: DENV proteins were screened against the host hn RNP H protein, in order to identify the host-viral protein-protein interactions in DENV infected THP-1 cells by co-immunoprecipitation. The co-localization of the interacting proteins was further confirmed by immunofluorescence microscopy. Results: The host protein hn RNP H was found to interact with DENV nonstructural 1 protein and help the virus to multiply in the cell. Conclusions: The non-structural 1 glycoprotein is a key modulator of host immune response and is also involved in viral replication. Therefore, disruption of this key interaction between hn RNP H and DENV nonstructural 1 could be an important therapeutic strategy for management of DENV infection.

Cleft analysis of Zika virus non-structural protein 1

The non-structural protein 1 is an important molecule of the viruses in flavivirus group including to Zika virus. Recently, the NS1 of Zika virus was discovered. There is still no complete information of the molecular interaction of NS1 of Zika virus which can be the clue for explanation for its pathogenesis and further drug search. Here the authors report the cleft analysis of NS1 of Zika virus and the result can be useful for future development of good diagnostic tool and antiviral drug finding for management of Zika virus.

Expression and Activity Analysis of Non-Structural Protein 2 (NS2) of Bombyx mori Densovirus Zhenjiang Strain

The gene of the non-structure protein 2 （NS2） was cloned by PCR from the genome ofBombyx mori densovirus Zhenjiang strain （BmDNV-Z）, inserted into prokaryotic expression vector pET28a to construct recombinant plasmid pET28a-NS2 and then expressed in bacteria Escherichia coli BL21 （DE3）. The expressed recombinant protein was identified by SDS-PAGE and Western blot analysis. Then, the recombinant protein was purified by Ni-NTA column, renatured and tested for enzyme activities. The purified NS2 protein exhibited a helicase activity unwinding double-stranded DNA substrates into single-strand primers, and higher unwinding activity to polarity substrate. Similarly, the purified NS2 protein possessed an ATPase activity and its enzyme activity was 0.276 μmol gg^-1 h^-1 in this study. The results indicated that the non- structure protein which encoded by the gene of BmDNV-Z NS2 possesses the biological activities of helicase and ATPase, and the helicase prefers to polarity substrates. Based on these results, it is speculated that the gene of BmDNV-Z NS2 plays an important role in the viral DNA replication.

Intracellular Transport of HIV-1 Matrix Protein Associated with Viral RNA

HIV-1 matrix protein (MA) is a multifunctional structural protein localized on N terminus of Gag precursor p55. MA participates in HIV-1 assembly as membranotropic part of Gag precursor as well as an individual protein spliced from Gag early in infection. MA is found in the nuclei of infected cells and in plasma membrane, the site of virus assembly, in association with viral genome RNA. MA mutated variant M4 which contains two changed amino acids in N-terminal regions is also associated with viral RNA, but it is localized in the nuclear and cytoskeleton fractions but not in the plasma membrane suggesting that the mutant is deprived of membranotropic signal and “sticks” in the nuclei an d cytoskeleton, its previous location sites. These data allow suggesting that MA involved into transmission of viral RNA is transported to plasma membrane by cytoskeleton.

Potential effect of hepatitis C Virus non-structural protein 4B on liver carcinogenesis

Objective：To investigate the effect of hepatitis C virus non-structural protein 4B（HCV NS4B） on c-Myc, P53, ras gene expression＂ and apoptosis in hepatic cells and study the possible role that NS4B played in the carcinogenesis of heparoma. Methods： The recombinant plasmid（PCXN2-NS4B, PCXN2-P53） and the empty, vector were transfected or co-transfected into Chang liver cells with liposome. Screening was performed with G418. Plasmid mRNA was detected by RT-PCR. The pro rein expressions of c-Myc and ras genes were analyzed by immunocytochemistry. The expressions of wild-type P53 （wtp53） gene were detected by in situ hybridization. TUNEL（flow cytometry） was used for assessing the rate of apoptosis. Results：No expression of c-Myc gene was found in PCXN2 group. The expression of c-Myc gene in NS4B group was 21.3% ＋ 1.2%. The ex pression of ras gene in PCXN2 group was lower than that in NS4B group. Compared with PCXN2 group, the expression of P53 mRNA was not promoted or inhibited in NS4B group. But the expression of P53 mRNA in NS4B-P53 group was lower than that in P53 group. In PCXN2, NS4B, P53 and NS4B-P53 group, the rates of apoptosis were 17.02% ± 1.24%, 11.94% ± 2.24%, 25.84% ± 3.49% and 18.34% ± 1.55% respectively. Conclusion ：HCV NS4B induces the expression of c-Myc and ras gene. HCV NS4B may play a role in the inhibition of cell death through P53-dependent manner. Results from this study suggested that HCV NS4B might contribute to the viral carcinogenesis.

Retraction Note:Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry

Retraction note:Khan M,Rauf W,Habib F,Rahman M,Iqbal M.Screening and identification of bioactive compounds from citrus against non-structural protein 3 protease of hepatitis C virus genotype 3a by fluorescence resonance energy transfer assay and mass spectrometry.World J Hepatol 2020;12(11):976-992 PMID:33312423 DOI:10.4254/wjh.v12.i11.976.The online version of the original article can be found at https://www.wjgnet.com/1948-5182/full/v12/i11/976.htm.

A Viral Expression Vector from Foxtail mosaic virus to Express Green Fluorescent Protein

[Objective]Foxtail mosaic virus(FoMV)infects gramineous and dicotyledonous plants.In this study,we sought to construct a viral vector based on FoMV to express exogenous proteins in plants.[Method]A recombinant viral expression vector was constructed by inserting the promotor of Potato virus X(PVX)and exogenous gene sequences into the 3’non-coding region of the FoMV coat protein gene.[Results]The plasmid pCB301-FoMV-CP-PVXprom-GFP expressed green fluorescent protein in inoculated Nicotiana benthamiana leaves.[Conclusion]A recombinant viral expression vector was constructed successfully.

牛病毒性腹泻病毒E2蛋白的真核表达及间接ELISA抗体检测方法的建立

为建立检测牛病毒性腹泻病毒(Bovine viral diarrhea virus,BVDV)抗体的间接ELISA方法,利用昆虫细胞真核表达系统成功表达E2蛋白,将纯化后的E2蛋白作为包被抗原,用方阵滴定方法对影响ELISA的各个因素进行优化,并进行特异性、敏感性和重复性试验。结果表明,在昆虫细胞中表达了BVDV E2蛋白,Western blot证实目的蛋白可与BVDV阳性血清发生特异性反应。ELISA优化结果显示,E2蛋白最佳包被浓度为0.5μg/mL,最佳封闭液为1%明胶,最佳血清稀释度为1∶400,最佳血清作用方式为37℃作用30 min,酶标抗体的最佳作用方式为1∶2000稀释、37℃作用30 min,最佳底物作用时间为室温20 min,阳性临界值为OD 450≥0.423。与血清中和试验法进行比较,总符合率为97.8%,板内和板间重复性试验的变异系数均小于10%。该方法与牛常见病毒阳性血清均无交叉反应。说明建立的间接ELISA抗体检测方法特异性、敏感性和重复性良好,可用于大批量样本的临床检测和流行病学研究。

牛病毒性腹泻病毒E^(rns)-ELISA抗体检测试剂盒的制备

为建立快速检测牛病毒性腹泻病毒(BVDV)的血清学方法,本试验以BVDV NADL毒株结构蛋白E^(rns)作为包被抗原,优化反应条件并组装BVDV酶联免疫吸附试验(ELISA)抗体检测试剂盒,通过重复性试验、灵敏性试验、符合率试验和保存期试验验证该试剂盒的准确性、灵敏性和稳定性。结果显示,抗原包被浓度为4μg/mL,1%酪蛋白溶液37℃封闭45 min,被检血清以1∶400稀释孵育30 min,兔抗牛HRP标记二抗以1∶20000稀释孵育30 min,TMB底物反应5 min时,ELISA的反应背景下降,区分度最好。优化后方法的批内重复性试验和批间重复性试验的变异系数均在10%以内,表明该试剂盒具有较好的稳定性;灵敏性试验结果显示,当阳性血清稀释度达到1∶6400时仍可以检测为阳性,说明该试剂盒灵敏度较高;该试剂盒与美国爱德士生物科技公司(IDEXX)BVDV总抗体检测试剂盒共同检测466份临床血清样品,两者总符合率为89.1%;保存期试验结果显示,第4个月时该试剂盒仍能检测到阳性血清,说明稳定性较好。综上表明,本试验利用E^(rns)蛋白建立的BVDV间接ELISA抗体检测试剂盒灵敏度高且重复性好,可为BVDV抗体检测和流行性调查提供新的方法。

黄芪多糖通过减轻免疫炎症抑制病毒性肝炎小鼠肝损伤

目的:观察黄芪多糖对病毒性肝炎小鼠肝损伤的影响,并探讨其是否能通过调控核苷酸结合寡聚化结构域1(NOD1)/受体相互作用蛋白2(RIP2)/核转录因子-κB(NF-κB)通路介导的免疫炎症发挥肝保护作用。方法:将60只雌性C3H/HeJ小鼠,采用随机数字表法分为建模组(50只)和正常组(10只)。建模组采用3型鼠肝炎病毒(MHV-3)腹腔注射建立病毒性肝炎小鼠模型,并于确定建模成功后将存活小鼠采用随机数字表法分为胸腺肽组(10μg)、黄芪多糖低、中、高剂量组(腹腔注射100、200、400 mg/kg黄芪多糖冻干溶于1 ml/100 g体质量的生理盐水)、模型组。模型组和正常组予以等量生理盐水腹腔注射,各组均每天给药1次,连续1个月。结果:经肝组织苏木素-伊红(HE)染色和病毒空斑数检测证实建模成功;与正常组比较,模型组小鼠肝脏指数,血清谷丙转氨酶(ALT)、谷草转氨酶(AST)、总胆红素(TBIL)、肿瘤坏死因子-α(TNF-α)、IL-1β、IL-8水平,肝组织病毒空斑数,肝组织NOD1、RIP2、NF-κB p65表达与p-NF-κB p65水平均升高(P<0.05),肝组织呈严重病理改变;与模型组小鼠比较,胸腺肽组和黄芪多糖各剂量组肝脏指数,血清ALT、AST、TBIL、TNF-α、IL-1β、IL-8水平,肝组织病毒空斑数,肝组织NOD1、RIP2、NF-κB p65表达与p-NF-κB p65水平均下降(P<0.05),肝组织病理改变均减轻,且黄芪多糖的作用呈剂量依赖性,胸腺肽组与黄芪多糖中剂量组比较上述指标差异均无统计学意义(P>0.05)。结论:黄芪多糖可改善病毒性肝炎小鼠的肝功能,减轻炎症反应和肝组织病理改变,降低病毒水平,推测与抑制NOD1/RIP2/NF-κB通路,下调NOD1、RIP2、NF-κB p65 mRNA与蛋白表达,抑制NF-κB p65磷酸化有关,且高剂量的黄芪多糖效果最佳,并优于胸腺肽-α1。

猪细小病毒病研究进展

猪细小病毒(Porcine parvovirus,PPV)是一种无囊膜DNA病毒,主要引起母猪繁殖障碍。该病毒在全世界广泛流行,我国猪场PPV感染率高达90%以上,给养猪业带来巨大经济损失。PPV经口、鼻传播,主要侵染猪的生殖器官,引起母猪的死胎、木乃伊胎和公猪的精液质量下降。临床采用接种疫苗的方式进行防控,起到了一定的效果。论文对病毒的基因组和蛋白特征、流行病学和疫苗研究进行综述,以期为PPV的基础研究和疫苗开发提供参考。

西藏地区结直肠癌免疫治疗和靶向治疗相关分子标志物的检测及意义

目的研究西藏地区结直肠癌中SWI/SNF相关、基质相关、肌动蛋白依赖性染色质调节因子A亚科成员4(SMARCA4)/Brahma相关基因1、V-raf鼠类肉瘤病毒癌基因同源物B(BRAF)、P53、程序性死亡受体1(PD-1)及程序性死亡配体1(PD-L1)免疫组织化学表达和BRAF、神经营养因子酪氨酸受体激酶(NTRK)基因改变情况,为西藏地区结直肠癌患者的靶向治疗及免疫治疗提供依据。方法收集2015年1月至2021年7月西藏自治区人民医院经手术切除病理确诊为结直肠癌病例64例,全部病例均进行SMARCA4、BRAF、P53、PD-1、PD-L1免疫组织化学染色和NTRK1、NTRK2、NTRK3融合基因荧光原位杂交检测及BRAF V600E基因突变PCR检测。结果64例结直肠癌病例男女比例1.21∶1,平均年龄(56.59±13.27)岁;46例(71.88%)位于结肠,18例(28.12%)位于直肠;60例(93.75%)为腺癌,4例(6.25%)为其他类型;11例(17.19%)为T1或T2期,53例(82.81%)为T3或T4期;24例(37.50%)出现淋巴结转移。免疫组织化学方面,64例中1例(1.56%)SMARCA4部分肿瘤细胞表达减弱或缺失,4例(6.25%)BRAF肿瘤细胞阳性表达,35例(54.69%)P53为突变型表达;45例(70.31%)PD-1肿瘤相关免疫细胞阳性比例分数<10%,19例(29.69%)≥10%;52例(81.25%)PD-L1联合阳性分数<10,12例(18.75%)≥10。64例NTRK1、NTRK2、NTRK3融合基因检测均为阴性;4例(6.25%)检测到BRAF V600E基因突变;1例SMARCA4表达缺失病例未检测到SMARCA4基因改变。PD-L1的表达与错配修复缺陷/高度微卫星不稳定和PD-1的高表达呈显著正相关(χ^(2)=10.223,P=0.001;χ^(2)=11.979,P=0.001)。结论西藏地区结直肠癌中较少出现SMARCA4表达减弱或缺失及NTRK融合基因改变,少数病例有BRAF V600E基因突变,Pan-TRK和BRAF免疫组织化学可作为NTRK融合基因及BRAF基因突变的初筛方法。错配修复缺陷/高度微卫星不稳定的病例中更容易出现PD-L1蛋白高表达,这部分患者有望获益于免疫治疗。P53突变与PD-L1表达无相关性,PD-1的高表达和PD-L1的高表达呈正相关。