Development of a radiolabeled site-specific single-domain antibody positron emission tomography probe for monitoring PD-L1 expression in cancer / 药物分析学报

Despite advances in immunotherapy for the treatment of cancers,not all patients can benefit from programmed cell death ligand 1(PD-L1)immune checkpoint blockade therapy.Anti-PD-L1 therapeutic effects reportedly correlate with the PD-L1 expression level;hence,accurate detection of PD-L1 expression can guide immunotherapy to achieve better therapeutic effects.Therefore,based on the high affinity antibody Nb109,a new site-specifically radiolabeled tracer,68Ga-NODA-cysteine,aspartic acid,and valine(CDV)-Nb109,was designed and synthesized to accurately monitor PD-L1 expression.The tracer 68Ga-NODA-CDV-Nb109 was obtained using a site-specific conjugation strategy with a radiochemical yield of about 95％and radiochemical purity of 97％.It showed high affinity for PD-L1 with a dissociation constant of 12.34±1.65 nM.Both the cell uptake assay and positron emission tomography(PET)imaging revealed higher tracer uptake in PD-L1-positive A375-hPD-L1 and U87 tumor cells than in PD-L1-negative A375 tumor cells.Meanwhile,dynamic PET imaging of a NC1-H1299 xenograft indicated that doxorubicin could upregulate PD-L1 expression,allowing timely interventional immunotherapy.In conclusion,this tracer could sensitively and dynamically monitor changes in PD-L1 expression levels in different cancers and help screen patients who can benefit from anti-PD-L1 immunotherapy.

Cerebellar ataxia, neuropathy, vestibular areflexia syndrome with replication factor C subunit 1 gene mutation: a case report and literature review / 中华神经科杂志

Objective:To investigate the clinical and genetic characteristics of cerebellar ataxia, neuropathy, vestibular areflexia syndrome (CANVAS) with replication factor C subunit 1 (RFC1) gene mutation to improve the understanding of this disease.Methods:A case of CANVAS diagnosed in the Peking University Third Hospital in January 2021 was reported. Detailed genetic analyses of ataxia were performed with DNA extracted from the peripheral blood of the patient. Studies including pathogenic variants of RFC1 gene causing CANVAS were reviewed and the clinical and genetic characteristics of the disease were summarized.Results:The patient was a 51-year-old female with the prominent manifestation of progressive walking instability. And the clinical data met the diagnostic criteria of CANVAS. The genetic tests excluded other hereditary ataxia mutations and identified the biallelic expansion of the pathogenic variant structure (AAGGG)exp repeat amplification in RFC1 gene. A total of 14 studies on CANVAS with RFC1 gene mutation were reviewed. The overall mutation rate of RFC1 gene in CANVAS was 68%-100%, and it varied in sporadic and familial CANVAS. And the mutation had ethnic differences.Conclusions:Among adult patients with late-onset ataxia, the combination of brain magnetic resonance imaging, electrophysiology tests and vestibular function examination is beneficial to the identification of CANVAS. And the genetic test of RFC1 gene has significant value in the diagnosis of this disease. This patient with CANVAS expands the disease spectrum of ataxia in China, and confirms that RFC1 gene mutation is of great significance in the screening of ataxia disorders in the Chinese population.

A case of sporadic adult-onset neuronal intranuclear inclusion disease presented with pure autonomic dysfunction / 中华神经科杂志

Neuronal intranuclear inclusion disease (NIID) is a slowly progressive neurodegenerative disease characterized by eosinophilic hyaline intranuclear inclusions in the central and peripheral nervous system, and also in the visceral organs. Although in recent years skin biopsy is useful for the antemortem diagnosis of this disease, it is often misdiagnosed due to its highly variable clinical manifestations. A case of NIID is reported here. The patient had a long course of disease, mainly presenting as dysfunction of autonomic nervous system. No significant cognitive impairment was found. Thus, a new idea is provided for the diagnosis of this disease.

Clinical characteristics of cerebral amyloid angiopathy-related inflammation / 中华神经科杂志

Objective:To investigate the clinical, cerebrospinal fluid (CSF) and neuroimaging characteristics and their associations with prognosis in cerebral amyloid angiopathy(CAA)-related inflammation (CAA-ri).Methods:Seventeen patients with CAA-ri, 59 patients with CAA-related intracerebral hemorrhage (ICH) and 15 patients with CAA-related cognitive decline were recruited from Huashan Hospital, Fudan University from November 2015 to May 2020 and the First Affiliated Hospital of University of Science and Technology of China from January 2018 to May 2020. Vascular risk factors and imaging features of cerebral small vessel disease were compared among three groups. Clinical manifestations, CSF results, lesion features on magnetic resonance imaging, treatment options and follow-up data were collected in patients with CAA-ri. The good prognosis was defined by clinical and radiographic improvement with no disease recurrence. The associations between clinical characteristics and the immunosuppressive therapy or the good prognosis were analyzed by binary Logistic regression models.Results:Patients with CAA-ri showed earlier disease onset [(61.5±11.7) years vs (70.9±8.6) years, t=9.428, P=0.001] and more lobar cerebral microbleeds [69.0 (43.5, 134.3) vs 10.0 (5.0, 59.0), H=3.363, P=0.002] compared to patients with CAA-ICH, and higher prevalence of male (14/17 vs 6/15, χ2=6.099, P=0.014) and lower white matter hyperintensity Fazekas score [4.0 (2.0, 6.0) vs 6.0 (5.0, 6.0), H=2.461, P=0.042] compared to patients with CAA-related cognitive decline. In patients with CAA-ri, the immunosuppressive therapy was positively correlated with CSF protein>600 mg/L (odds ratio 16.50, 95% confidence interval 1.09-250.18, P=0.043), and during a follow-up of (3.0±1.9) years, the good prognosis was positively correlated with CSF protein<1 000 mg/L plus immunosuppressive therapy (odds ratio 20.00, 95% confidence interval 1.39-287.60, P=0.028). Conclusions:CAA-ri is a special subtype of CAA with earlier disease onset and higher prevalence of hemorrhagic imaging makers compared to CAA-ICH and CAA-related cognitive decline. CAA-ri patients with normal or slightly elevated CSF protein receiving immunosuppressive therapy are more likely to have good prognosis.

Diagnosis, management and research prospect of embolic strokes of undetermined source / 中华神经科杂志

Embolic strokes of undetermined source (ESUS) is the non-lacunar ischemic stroke without intracranial and extracranial arterial stenosis and overt cardiac embolism. This article reviews the etiology, classification, diagnosis and management of ESUS with related clinical trials and discusses its future research.

Inhibition of K562 cell growth and tumor angiogenesis in nude mice by antisense VEGF(121) cDNA transfection / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the effect of antisense vascular endothelial growth factor (VEGF)(121) cDNA transfection on the growth of K562 cells in nude mice.</p><p><b>METHODS</b>K562 cells transfected with the antisense (AS) or sense (S) VEGF(121) cDNA, and the vector (V, pcDNA3) alone were transplanted subcutaneously into nude mice and the growth of the transfected cells in vivo was investigated. The effects of transfected K562 cells on human bone marrow endothelial cells (BMEC) were analyzed by MTT assay, the microvessel density (MVD) in tumor mass by vWF immunohistochemistry stain.</p><p><b>RESULTS</b>K562/V tumor grew more slowly [(207.5 +/- 192.9) mm(3) vs (445.0 +/- 150.9) mm(3), P < 0.05] and K562/S tumor more rapidly than K562/V tumor did [(1 174.6 +/- 508.7)/mm(3) vs (445.0 +/- 150.9) mm(3), P < 0.01]. K562/S cell culture supernatant was more strongly in promoting the proliferation of BMEC than K562/V supernatant did, but K562/AS supernatant resulted in a marked decrease of the promoting effect as compared with K562/V's. The MVDs in K562/AS, K562/S, and K562/V tumors were [(11.0 +/- 7.6)/0.72 mm(2) vs (50.8 +/- 11.7)/0.72 mm(2) vs (18.9 +/- 7.0)/0.72 mm(2)], respectively.</p><p><b>CONCLUSIONS</b>Antisense VEGF(121) cDNA transfected K562 cells show growth retardation in transplanted nude mice, decrease of tumor MVD, and decrease of promoting BMEC proliferation capacity.</p>

The mechanism of STI571 inducing apoptosis of K562 cells / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate the mechanism of STI571 inducing apoptosis of K562 cells which express P210(BCR/ABL).</p><p><b>METHODS</b>Apoptosis was analyzed by Annexin-V/PI, DioC6 [3] staining, DCFH-DA staining, DNA-PI staining and DNA ladder. Western blot was used to analyse mitochondrial and cytosolic cyto C, Bcl-X(L), caspase-3, actin protein and the level of tyrosine phosphorylation.</p><p><b>RESULTS</b>After exposure to STI571, K562 cells were induced to apoptosis. Tyrosine phosphorylation level of P210(BCR/ABL) and Bcl-X(L) was decreased. Caspase-3 was activated and there was an cytosolic accumulation of cyto C.</p><p><b>CONCLUSION</b>STI571 could rapidly decrease the tyrosine phosphorylation level of P210(BCR/ABL). The signal pathway mediated by the cytosolic translocation of mitochondrial cyto C was one of the mechanisms that STI571 inducing apoptosis. STI571 was an effective gene targeting therapeutic agent.</p>

The Function of Dendritic Cells Derived from Chronic Myeloid Leukemia / 中国实验血液学杂志

The purpose of this study was to investigate the function of dendritic cells derived from chronic myeloid leukemia (CML-DC). Mononuclear cells were prepared from bone marrow and peripheral blood of 24 patients with CML, and the DCs were obtained by incubation of MNCs with media containing GM-CSF, IL-4 and TNF-alpha. The phenotype of CML-DCs was identified by flow cytometry. FITC-dextran uptake, (3)H-TdR incorporation or MTT assay and lactate dehydrogenase release assay were used to detect uptake of exogenous antigen in immature DCs, the antigen presenting ability in mature DCs and specific cytotoxicity of CTL to leukemic cells, respectively. The DCs with high expression of CD1a, CD86, CD80, HLA-DR, CD54 and CD4 were obtained from marrow and blood of patients with CML. The uptake of FITC-DX was observed in early DCs. There was a potent stimulation to allo-MLR in DCs cultured for 7 - 10 days, and a lightly lower stimulation to auto-MLR. CML-DCs can induce the generation of specific cytotoxic T cells. These results suggest that CML-DCs are functional DCs with the ability to induce anti-leukemia effect.

beta1 Integrin Dysfunction in Adult Chronic Myeloid Leukemia Bone Marrow Cells / 中国实验血液学杂志

According to our previous experiments, Ph(+) chronic myeloid leukemia (CML) cell line K562 cells have defects in beta 1 integrin activation. In order to search the same regularity in Ph(+) CML bone marrow cells, bone marrow mononuclear cells (BMMNC) from 12 cases of Ph(+) CML and 10 cases of normal individuals were studied. Their expression rate of 9EG7 epitope on beta1 integrin post treatment by 8A2 or GM- or G-CSF and cell adhesion ability with soluble fibronectin (FN) were evaluated by flow cytometry; in addition, the effects of CGP57148B, a highly specific ABL tyrosine kinase inhibitor, were observed. Our results showed that 9EG7 expression rate and FN binding rate were very low in all the inactivated cells. The parameter increased markedly post 8A2 activation in both NBMMNCs and CMLBMMNCs, but the degree of increase in CMLBMMNCs was significantly lower than that in NBMMNCs; GM-CSF or G-CSF could significantly increase the parameters in NBMMNCs while had no effects on that in CMLBMMNCs. CGP57148B could increase the beta1 integrin activation potential of CMLBMMNCs but had no effects on that of NBMMNCs. The results indicate that decreased activation potential of beta1 integrin in CMLBMMNCs is the major cause of adhesion defects of Ph(+) CML cells; beta1 integrin functional insufficiency in CMLBMMNCs could not be directly reversed by ABL tyrosine kinase inhibitor CGP57148B.