TGF-ß1-Mediated PD-L1 Glycosylation Contributes to Immune Escape via c-Jun/STT3A Pathway in Nasopharyngeal Carcinoma.

Immunotherapy targeting programmed death ligand-1/programmed cell death protein-1 (PD-L1/PD-1) has achieved great success in multiple cancers, but only a small subset of patients showed clinical responses. Recent evidences have shown that post-translational modification of PD-L1 protein could regulate its protein stability and interaction with cognate receptor PD-1, thereby affecting anticancer immunotherapy in several solid tumors. However, the molecular mechanisms underlying how PD-1/PD-L1 expression is regulated still remain unclear in nasopharyngeal carcinoma (NPC). Here, we found N-glycosylation of PD-L1 in NPC cells and tissues. Mechanistically, we showed that STT3A transferred N-linked glycans to PD-L1, and TGF-ß1 could positively regulate STT3A expression through activating c-Jun to bind to STT3A promoter. Functional assays showed that inhibition of TGF-ß1 resulted in a decrease of glycosylated PD-L1 and enhanced cytotoxic T-cell function against NPC cells. Analysis of clinical specimens revealed that the expression of STT3A was positively correlated with TGF-ß1 and c-Jun, and high STT3A expression was positively correlated with a more advanced clinical stage. Altogether, TGF-ß1 activated c-Jun/STT3A signaling pathway to promote N-glycosylation of PD-L1, thus further facilitating immune evasion and reducing the efficacy of cancer immunotherapy. As such, all these data suggested that targeting TGF-ß1 pathway might be a promising approach to enhance immune checkpoint blockade, and simultaneous blockade of PD-L1 and TGF-ß1 pathways might elicit potent and superior antitumor activity relative to monotherapies.

Dynamic Characteristics and HIV Infection of Men who have Sex with Men from 2011 to 2017 in Yinchuan, Ningxia, China.

OBJECTIVES: Ningxia Hui Autonomous Region, an important area for ethnic Hui settlement in Northwest China, is a low HIV prevalence region. However, HIV infection rates among men who have sex with men (MSM) in Ningxia have increased to an alarming level, despite scale-up of control measures in recent years. This study aimed to understand the demographical and sexual behavior dynamics of MSM and to explore the factors associated with HIV infection. METHODS: Annual cross-sectional surveys were carried out among MSM during 2011~2017 in Yinchuan, the capital city of Ningxia. Information regarding social demographics, sexual behavior and HIV prevention knowledge was collected. Blood samples were taken for HIV, HCV serological and genetic analysis, and syphilis serological analysis. The dynamic trend was analyzed with trend χ2 test and factors associated with HIV infection were identified by multivariate logistic regression analysis. RESULTS: The study found a decreasing trend for mean age of the MSM population over the study period. MSMs with a college education or higher increased significantly, while the proportions that were in a marriage significantly decreased over the study period. The rate of HIV positive among MSM increased during the study period (p<0.05), however, the rate of recently diagnosed infections decreased from 2012 (p<0.05). Overall, a very high proportion (98%) of MSM had basic knowledge of HIV prevention, however, only approximately 40% of them used condoms consistently during anal sex with male partners. Unprotected anal sex was identified as a risk factor associated with HIV infection, as was syphilis infection. Local residency status and MSM who received intervention and detection services were the factors that decreased HIV infection risk. Sequence analysis identified the HIV-1 CRF55_01B subtype from MSM for the first time in Yinchuan. CONCLUSION: The reduction of recent HIV diagnoses is an encouraging sign of successful HIV control measures in MSM in Ningxia. The finding that a high proportion of MSM had knowledge of HIV prevention but still conducted unprotected sex highlights the need for further control measures to change unsafe sexual practices among MSM.

[Typing and identification of non-polio enterovirus from acute flaccid paralysis cases in Ningxia, 1997-2011].

OBJECTIVE: To identify the serotype of 73 non-polio enterovirus (NPEV) strains from acute flaccid paralysis (AFP) cases in Ningxia province, during 1997 - 2011. METHODS: Partial sequencing of the VP1 region was amplified by RT-PCR with degenerate primers and sequenced while sequences were compared with the database of GenBank by the BLAST algorithm. Evolution was analyzed by constructing phylogenetic tree using Mega 5.1. RESULTS: In this study, a total of 73 NPEVs were analyzed, including 4 strains un-typed, 69 strains typed by RT-PCR. A total of 27 serotypes were identified, including 8 serotypes of human enterovirus (HEV)-A, 19 serotypes of HEV-B. The HEV-B group (46/69, 66.7%) constituted the largest proportion of isolates, followed by HEV-A (23/69, 33.3%), but no strains were found that belonged to HEV-C or HEV-D group. In the 69 strains, enterovirus 71 was the most frequently seen isolates, followed by coxsackie-virus A4, 16, 9 and echovirus 24, 6. CONCLUSION: HEV-B was the most predominant (46/69, 66.7%) serotype of NPEV in Ningxia during the AFP surveillance, in 1997 - 2011.

[Genetic characterization of coxsackievirus A16 isolated in Ningxia Hui Municipality in 2008].

OBJECTIVE: To study the genetic characterization of coxsackievirus A16 (CVA16) strains isolated during an epidemic of hand, foot, and mouth disease (HFMD) in Ningxia Hui Municipality in 2008. METHODS: Clinical samples were collected from HFMD patients in Ningxia Hui Municipality and CVA16 strains were isolated by viral isolation methods. Reverse transcription-polymerase chain reactions (RT-PCR), specific for CVA16 were performed with these CVA16 strains. Entire VP1 coding region amplification and sequencing were then performed and finally phylogenetic tree was constructed among Ningxia CVA16 strains and CVA16 representative strains of known genotypes and subgenotypes. RESULTS: 70 Ningxia CVA16 strains were isolated from HFMD patients in Ningxia in 2008 and the homology of nucleotide and amino acid were 90.8%-100.0% and 98.9% - 100.0%, respectively. Phylogenetic characteristics of the strains reconfirmed that they could be divided into two distinct genotypes-A and B. Genotype B could be further divided into the subgenotypes B1 and B2, while all the 70 Ningxia CVA16 strains belonged to the co-circulated clusters B1a and B1b within subgenotype B1, which belonged to 2 viral transmission chains. CONCLUSION: Our results indicated that subgenotype B1 CVA16 strains continued to circulate over a wide geographic area of mainland China since the first reported episode in Shenzhen city in 1999. Like other CVA16 strains isolated elsewhere in China, both B1a and B1b evolution branches were co-circulating in Ningxia Hui Municipality. Based on the close phylgenetic and chronological relationship with CVA16 isolated in other countries and regions near China. Our data confirmed that these strains co-evolved and co-circulated with those from neighboring countries and regions.

[Genetic characterization of enterovirus 71 stains isolated in Ningxia province in 2008].

OBJECTIVE: To study the genetic characterization of enterovirus 71 (EV71) strains isolated from specimens of patients with hand-foot-mouth disease (HFMD) in Ningxia province in 2008. METHODS: All the stool, throat swab and vesicle samples that collected from patients with HFMD were cultured. The positive isolates were identified by reverse transcriptase PCR (RT-PCR) with specific primers of EV71. Complete VP1 gene sequences (891 nucleotides) of 29 strains (part of 93 EV71 strains) were determined and compared with A, B and C genotype reference EV71 strains while EV71 China isolates by homogeneity and phylogenetic tree analyses. RESULTS: 215 strains of EV were isolated from 439 specimens. Results from RT-PCR indicated that 93 strains belong to EV71. Phylogenetic tree analysis revealed that the selected 29 stains were clustered with reference strains of C4 subgenotype. The nucleotide identity with C4 reference strains was 91.7%-99.4%. The amino acid homogeneity was 96.6%-100.0%. CONCLUSION: The recently identified EV71 strains in Ningxia province belonged to subgenotype C4 which resembled to most of the isolates in China.

[A new isoflavone from Huoxue Yiqi Tang].

OBJECTIVE: To study the chemical constituents in the active parts of Huoxue Yiqi Tang. METHOD: The silica gel, Sephadex LH-20 were used to isolate the compounds, El, FAB-MS and 1D, 2D-NMR were used to identify the obtained compounds. RESULT: 14 compounds were obtained from the prescription. CONCLUSION: They were all first time obtained from the prescription. Among them, 7, 3'-dihydroxyl-5'-methoxyisoflavone is new.

[Isolation and identification of a new cucurbitacin from Picria fel-terrae].

AIM: To study compounds isolated from Picria fel-terrae. METHODS: The chemical constituents were separated and purified by column chromatography on silica gel and MCI. Their structures were identified on the basis of spectral data (IR, UV, MS, ID NMR and 2D NMR). RESULTS: A new cucurbitacin, along with a known one, were obtained from the 60% EtOH extract of the whole plant. CONCLUSION: The new compound was identified as 11, 24-dioxo-5, 21-diene-cucurbit-3alpha-O-beta-D-xylopyranosyl-16alpha-O-alpha-L-rhamnopyranoside (dehydrobryogenin glycoside). The known one, hexanorcucurbitacin F, was obtained for the first time from Picria fel-terrae.

[Study on the chemical constituents from Picria fel-tarrae].

OBJECTIVE: To isolate and identify compounds from Picria fel-tarrae in order to utilize it better. METHOD: Constituents from Picria fel-tarrae were isolated by several column chromatography and their structures were elucidated on the basis of chemical and spectral analysis. RESULT: Six compounds, N-benzoylphenylalanyl-L-phenylalaninol acetate (1), 1-hydroxy-7-hydroxymethyl-9,10-anthraquinone (2), 9, 16-dioxo-10,12,14-octadeca-trienoic acid (3), 5,7,4'-trihydroxy-flavone (4), beta-sitosterol (5), and daucosterol (6) were obtained from the fraction with relatively low polarity of EtOH extract of Picria fel-tarrae. CONCLUSION: Compounds 1-6 were isolated from picria fel-tarrae Lour for the first time, and the 13C-NMR data of compounds 1-3 are provided firstly in the literature.