Serum antibody levels in COVID-19 patients six months after hospital discharge / 上海预防医学

ObjectiveTo investigate the level of serum antibodies in COVID-19 patients six months after discharge， and to provide data to evaluate the duration of IgM， IgG and neutralizing antibody titers in the patients. MethodsEnzyme-linked immunosorbent assay （ELISA） was used to determine the antibody levels of IgM and IgG， and the new coronavirus live virus neutralization test was used to detect the neutralizing antibodies in the plasma of 181 recovered patients. ResultsThe IgG positive rate was 92.27% （167/181） in COVID-19 patients six months after discharge， while the lgM positive rate was 28.18% （51/181）. Six months after hospital discharge， 117 recovered patients （64.64%） were positive for IgG antibodies and negative for IgM antibodies， indicating that they had produced stable antibodies. This result suggested that they had been infected with the new coronavirus （SARS-CoV-2） and were in the recovery stage. The positive detection rate of neutralizing antibodies was as high as 91.71%. ConclusionSix months after infection with SARS-CoV-2， IgG antibodies produced in the patients continue to exist， and the neutralizing antibodies maintain a high and stable level. Results of this study have important guiding significance for future research on the durability of new coronavirus antibodies.

Serum antibody levels in COVID-19 patients six months after hospital discharge / 上海预防医学

ObjectiveTo investigate the level of serum antibodies in COVID-19 patients six months after discharge， and to provide data to evaluate the duration of IgM， IgG and neutralizing antibody titers in the patients. MethodsEnzyme-linked immunosorbent assay （ELISA） was used to determine the antibody levels of IgM and IgG， and the new coronavirus live virus neutralization test was used to detect the neutralizing antibodies in the plasma of 181 recovered patients. ResultsThe IgG positive rate was 92.27% （167/181） in COVID-19 patients six months after discharge， while the lgM positive rate was 28.18% （51/181）. Six months after hospital discharge， 117 recovered patients （64.64%） were positive for IgG antibodies and negative for IgM antibodies， indicating that they had produced stable antibodies. This result suggested that they had been infected with the new coronavirus （SARS-CoV-2） and were in the recovery stage. The positive detection rate of neutralizing antibodies was as high as 91.71%. ConclusionSix months after infection with SARS-CoV-2， IgG antibodies produced in the patients continue to exist， and the neutralizing antibodies maintain a high and stable level. Results of this study have important guiding significance for future research on the durability of new coronavirus antibodies.

Correlation between FOXP3, CD11c Protein Expression and Prognosis of Patients with Diffuse Large B-cell Lymphoma / 中国实验血液学杂志

OBJECTIVE@#To investigate the correlation between FOXP3, CD11c protein expression and the prognosis of patients with diffuse large B-cell lymphoma (DLBCL).@*METHODS@#This study included 48 patients with DLBCL who were admitted to Jiujiang No.1 People's Hospital and TCM-Integrated Hospital of Southern Medical University from January 2015 to January 2019. The DLBCL tissues removed during the operation were collected as test specimens. The expression of FOXP3 and CD11c protein were detected by immunohistochemistry. The deadline for postoperative follow-up was December 31, 2019, and the patient's short-term efficacy (complete remission, partial remission) and progression-free survival were recorded.@*RESULTS@#FOXP3 protein was positively expressed in the nucleus, mostly focally or diffusely distributed, the FOXP3@*CONCLUSION@#In some patients with DLBCL, FOXP3 and CD11c expresse positively, and the positive expression rate is related to the clinical stage and international prognostic index score. The positive expression of FOXP3 and CD11c indicate a good prognosis.

Effects of activation or blockade of 5-HT1A receptors in the medial septum-diagonal band of Broca complex on cognitive functions in hemiparkinsonian rats / 西安交通大学学报(医学版)

Objective To explore the role and mechanisms of 5-HT1Areceptors in the medial septum-diagonal band of Broca complex (MS-DB) in hemiparkinsonian rats. Methods Combined behavioral and electrophysiological studies were performed to assess the role of MS-DB 5-HT1Areceptors in working memory and hippocampal theta rhythm in rats with 6-hydroxydopamine (6-OHDA)lesions in the medial forebrain bundle (MFB).Results ① MFB lesions in the rats decreased choice accuracy in the T-maze rewarded alternation test. Intra-MS-DB injection of 5-HT1Areceptor agonist 8-OH-DPAT further decreased choice accuracy,while intra-MS-DB injection of 5-HT1Areceptor antagonist WAY-100635 increased choice accuracy in the lesioned rats.② MFB lesions in the rats decreased peak theta rhythm frequency. Intra-MS-DB injection of 8-OH-DPAT suppressed hippocampal theta rhythm and decreased normalized theta power,while intra-MS-DB injection of WAY-100635 induced theta rhythm and increased normalized theta power.Conclusion Blockade of MS-DB 5-HT1Areceptors can recover cognitive dysfunction in Parkinson's disease, which may be attributed to the enhancement of hippocampal theta rhythm.

Multiple primary sarcomatoid carcinoma of the jejunum with postoperative lung and brain metastases: a case report and literature review / 南方医科大学学报

We report a rare case of a multiple sarcomatoid carcinoma of the jejunum with postoperative lung and brain metastases. The patient underwent jejunum segmental resection for intussusception and gastrointestinal bleeding. Multiple metastasis ofbrain and lung occurred 4 months after the operation, and the patient died for multiple organ failure 8 months after the surgery. Primary sarcomatoid carcinoma was difficult to diagnose at an early stage, and the diagnosis relies on optical microscopic and immunohistochemical observations. Currently no guidelinesare established for treatment for sarcomatoid carcinoma of the jejunum, and surgical resection remains the optimal therapeutic approach. Previous reports documented a poor prognosis of the patients with a median survival time of 5.5 months (0.36-36months), and the primary causes of death were tumor recurrence and metastasis. Ki-67 as a potential prognostic marker and the value of PD-L1-targeted immunotherapy for the treatment await further investigation.

A rare fatal case of a novel bunyavirus-associated hemophagocytic lymphohistiocytosis.

Herein we describe a rare fatal case of a novel bunyavirus-associated hemophagocytic lymphohistiocytosis (HLH) in a 62-year-old female patient. The novel bunyavirus infects patients with or without HLH who have similar clinical features such as fever, thrombocytopenia, and leukocytopenia. Therefore, the diagnosis of HLH can be easily missed. When HLH occurs, the disease worsens and the fatality rate rises. Our finding highlights the importance of bone marrow biopsy performed as soon as possible for patients suspected of having a novel bunyavirus infection and showing marked cytopenia in three cell lines.

[The induced differentiation and apoptosis of THP-1 cells by anti-CD44 antibody and its mechanism].

OBJECTIVE: To investigate the effects of anti-CD44 mAb A3D8 on the cell proliferation of human acute monocytic leukemia cell line THP-1 and its mechanism. METHODS: Cell proliferation was assayed with MTT method, the expression of CD33, CD15, CD11b, CD14, Annexin-V, caspase-3 and cell cycle with flow cytometry, and the expression of p-Akt, p-ERK, bcl-2 and p27kip1 with Western blot. RESULTS: A3D8 could remarkably inhibit the proliferation capacity of the THP-1 cells in a dosage- and time-dependent manner. THP-1 differentiation was observed when treated with A3D8 (2.0 µg/ml) for one to six days. Expression of CD33 (68.9 ± 2.0 vs 39.3 ± 1.5), CD15 (61.7 ± 5.5 vs 12.9 ± 2.6), CD11b (67.3 ± 3.8 vs 14.0 ± 2.0) and CD14 (83.0 ± 5.7 vs 8.0 ± 1.0) was significantly increased at day 4 compared with the control group (all P < 0.01). Cell cycle of the THP-1 cells was arrested in G(0)/G(1). Expression of the Annexin-V \[(32.5 ± 2.5)% vs (2.4 ± 0.3)%\] and caspase-3 \[(33.3 ± 2.5)% vs (3.6 ± 0.3)%\] was much higher than that in normal controls (all P < 0.01), and apoptosis was observed in THP-1 cells at day 5. Expression of p-Akt (0.24 ± 0.06 vs 1.20 ± 0.15), p-ERK (0.32 ± 0.05 vs 1.24 ± 0.09), and bcl-2 (0.11 ± 0.05 vs 0.65 ± 0.07) was much lower than that of the controls (all P < 0.01), while p27kip1 (1.08 ± 0.09 vs 0.10 ± 0.02) was significantly increased at day 4 (P < 0.05). CONCLUSION: Anti-CD44 antibody can induce the differentiation and apoptosis of THP-1 cell through inhibiting PI3K/AKt and ERK1/2 signaling pathway.

[Expression of CD123 in lymphocytic leukemia and its significance for monitoring minimal residual diseases.].

OBJECTIVE: To investigate the expression of CD123 and its significance in lymphocytic leukemia. METHODS: CD123 expression in 139 lymphocytic leukemia patients and in lymphocytes from 10 normal bone marrows (BM) was analyzed by multi-parameter flow cytometry. Cytogenetic and minimal residual disease (MRD) analysis were performed in acute B-lymphocytic leukemia (B-ALL) patients. RESULTS: CD123 expression was absent in B lymphoid lineage stem-progenitor cells, mature B and T lymphocytes from 10 normal BM. Among 139 lymphocytic leukemia patients, CD123 was negative in 5 T-ALL and 23 B-CLL patients. However, among 111 B-ALL patients, CD123 was expressed in 106 (12 pro B-ALL, 57 common B-ALL and 37 Pre B-ALL) (95.49%) but not in 5 mature B-ALL patients. There was a positive correlation between CD123 and p-Akt expression, and CD123 expression was much higher in hyperdiploid than in non-hyperdiploid B-ALL patients. A statistically significant difference in relapse rate within 12 months (MRD positive group: 63.04% vs MRD negative group 21.56%)and in disease free survival (DFS) time was found beween patients with MRD\[(36.06 +/- 2.62)%\] or not \[(48.23 +/- 1.82)%\] (P < 0.01). Moreover, stable CD123 expression could be observed in B-ALL patients in relapse. CONCLUSIONS: CD123 was predominantly expressed in B-ALL patients and remained in patients in relapsec, indicating that it may be an useful MRD marker in B-ALL patients.

[Effect of rapamycin on apoptosis in human myelodysplastic syndrome cell line MUTZ-1 and its possible mechanisms].

The aim of this study was to investigate the effect of rapamycin on cell growth and apoptosis in the myelodysplastic syndrome (MDS) cell line MUTZ-1 and possible mechanism. MUTZ-1 cells were treated with rapamycin, cell proliferation capability was determined with MTT, protein expression including Annexin V/PI, caspase 3, PTEN, p-Akt, p-mTOR and the cell cycle were analyzed with flow cytometry. The results indicated that the proliferation of MUTZ-1 cells was inhibited by rapamycin in concentration-and time-dependent manners (r=0.67, 0.61, 0.72). After treatment with rapamycin for 24-72 hours, cell count in G0/G1 were significantly higher than that of the control (p<0.01), and this effect showed a time-and concentration-dependency (r=0.94, 0.93, 0.92), the cell cycle was blocked in G0/G1 phase. As compared with control group, the proportion of Annexin V+PI-MUTZ-1 cells and the cellular PTEN levels increased in the treated group dramatically and in time-and dose-dependent manners (p<0.01). To the contrary, level of p-mTOR expression markedly decreased as compared with control group (p<0.05). It is concluded that the rapamycin inhibits the proliferation of MUTZ-1 cells, down-regulates the PTEN/PI3K-Akt/mTOR signaling pathway by interaction with mTOR, which induces the apoptosis of mUTZ-1 cells.

Inhibitory effect of photodynamic therapy combined with paclitaxel on the proliferation of esophageal carcinoma Eca-109 cells / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the inhibitory effect of photodynamic therapy (PDT) in combination with paclitaxel (PCT) on proliferation in esophageal carcinoma Eca-109 cells line.</p><p><b>METHODS</b>Eca-109 cells were treated with PCT alone, HPD alone at different doses, or their combinations. For the combined treatments, the cells were exposed to PCT for 12 h followed by incubation with HPD at high, middle or low concentrations for 4 h. PDT was then performed on these treated cells and fluorescence microscopic observation was made before and after PDT. The cell survival was measured by MTT assay, and the cell apoptosis rate analyzed by flow cytometry after a 24-h cell incubation following PDT.</p><p><b>RESULTS</b>The fluorescence excitation of the cells was weakened after PDT. Combined treatments resulted in significantly lowered cell survival rate and increased cell apoptosis rates as compared to those of the control cells and the cells treated with PCT alone and low-dose HPD (P<0.01). Significant differences were also noted among the cells exposed to HPD at different concentrations (P<0.05).</p><p><b>CONCLUSION</b>PDT combined with PCT have significant synergetic effects in inhibiting the proliferation of human esophageal carcinoma cells and inducing their apoptosis in vitro.</p>

Mechanism of photodynamic therapy against human esophageal carcinoma xenografts in nude mice / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the mechanism of photodynamic therapy (PDT) in nude mice bearing human esophageal cancer cell line Eca-109 xenografts.</p><p><b>METHODS</b>A nude mouse model bearing human esophageal carcinoma was established by subcutaneous transplantation of Eca-109 cells. The mice were then randomized into 4 groups, namely hematoporphyrin derivative (HpD)-PDT group (given HpD and laser irradiation), exclusive laser irradiation group, exclusive HpD group and blank control group. In HpD-PDT group, the mice were exposed to irradiation at the light energy density of 120 Jsol;cm(2) delivered via a DIOMED 630 PDT system 24 h after intraperitoneal HpD injection, and the mice in exclusive laser irradiation group received only laser irradiation. Three days later, all the nude mice were sacrificed for determination of malondialdehyde (MDA) production, immunohistochemistry for caspase-3 protein and HE staining of the tumor tissue.</p><p><b>RESULTS</b>The MDA level was significantly higher in HpD-PDT group than in the other 3 groups (P<0.01), and comparable between the latter 3 groups. Expression of caspase-3 protein was similar between HpD-PDT group and the blank control group (P>0.05). Under light microscope, HE staining visualized massive tissue necrosis in HpD-PDT group with homogeneous red staining.</p><p><b>CONCLUSION</b>In human esophageal carcinoma xenografts in nude mice, HpD-PDT generates singlet oxygen to result in direct tumor cell damage and cause MDA production. Caspase-3 may not be activated in the apoptotic pathway, suggesting that this pathway may not be caspase-3-dependent.</p>

Biology of thioredoxin and its association with Alzheimer's disease and Parkinson's disease / 药学学报

Thioredoxin (Trx) is a crucial protein for antioxidative defense, as well as a redox regulator of the intra- and extracellular signaling pathways and transcription factors. In this review, we focus on mammalian Trx and its association with Alzheimer's disease (AD) and Parkinson's disease (PD). Based on the evidence of neuroprotective effects of Trx, up-regulation of Trx may be a good strategy for prevention and treatment of AD and PD.

[The correlation study of PTEN gene expression and Akt phosphorylation in myelodysplastic syndrome].

OBJECTIVE: To investigate the relationship between PTEN gene expression and Akt phosphorylation (p-Akt) in myelodysplastic syndrome (MDS) and to explore the progression of MDS and the mechanism of high risk transformation to acute myeloid leukemia. METHODS: RT-PCR was used to detect the PTEN mRNA expression in leukemia cell lines K562 (as negative control) and Jurkat (as positive control) and 65 MDS and MDS/AML patients. Flow cytometry was used to detect p-Akt in HL-60 and Jurkat cells and 30 MDS patients. RESULTS: (1) K562 cells present PTEN gene expression while Jurkat cells did not. Of 65 MDS and MDS/AML patients, 27 (41.5%) expressed PTEN mRNA, being significantly lower than that in normal group (85.7%) (P < 0.01). (2) Jurkat cell showed high expression (86.9%) of p-Akt, while HL-60 cell as negative control did not express. P-Akt levels of 30 MDS patients were increased (1.35% - 58.23%), being much higher as compared with that of the normal contrast group (0.54% - 2.34%) (P < 0.01). Moreover, with the rate of blast cells increasing, the p-Akt level was rising up. There is a positive correlation (r = 0.93, P < 0.01) between the low expression rate of PTEN and the positive rate of p-Akt. CONCLUSION: The loss of PTEN gene expression is one of the important factors of p-Akt high expression in MDS patients, moreover, it may speed up the progress of the MDS or transformation to acute myeloid leukemia.

Possible roles of KIR2DL4 expression on uNK cells in human pregnancy.

PROBLEM: To investigate possible roles of the natural killer (NK) cell receptor killer immunoglobulin-like receptor (KIR)2DL4 expressed on uterine NK (uNK) cells during pregnancy, we investigated KIR2DL4 expression on uNK cells isolated from patients with early recurrent spontaneous abortion (RSA) and normal early pregnancy women, and functions of KIR2DL4 was analyzed in vitro. METHODS OF THE STUDY: Semi-quantitative RT-PCR analysis was introduced to detect KIR2DL4 messenger RNA (mRNA) expression on uNK cells. Cytotoxicity and cytokine production as the result of interaction of KIR2DL4 and its ligand human leukocyte antigen (HLA)-G were analyzed in vitro with lactic dehydrogenase releasing method and enzyme-linked immunosorbent assay, respectively. RESULTS: No significant difference in KIR2DL4 mRNA expression was observed, while the KIR2DL4 protein level in isolated uNK cells is much higher in normal controls than that in RSA patients. Data showed that HLA-G transfection could not reverse the lysis of uNK against HLA-G transfected K562 cells but induced cytokine production. Furthermore, we demonstrated that, via KIR2DL4, membrane-bound HLA-G could induce high cytotoxicity and cytokine production in a high cytotoxic, IL-2 dependent human NK cell line NK-92 cells. CONCLUSION: Our data suggest that KIR2DL4 might play a crucial implication for human pregnancy.

Main factors affecting the effect of photodynamic therapy against human esophageal cancer cells in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To evaluate the tumor cell-killing effect of photodynamic therapy against human esophageal cancer cells in vitro and identify the main factors affecting the effect.</p><p><b>METHODS</b>Human esophageal cancer Eca-109 cells were incubated for 24 h in vitro with hematoporphyrin derivative (HpD) and Photofrin at different concentrations prior to exposure to a light energy density of 15 J/cm(2) delivered from a DIOMED 630 PDT system. The cell killing effect was also evaluated for different HpD concentrations combined with 3 light energy densities (10, 30, and 50 J/cm(2)), respectively. The cell survival rate was measured using MTT assay, and fluorescence spectrometry was used to detect the intracellular photosensitizer fluorescence of the tumor cells after incubation with HpD for 4 h.</p><p><b>RESULTS</b>The cell survival rate after incubation with the two photosensitizers at different concentrations were significantly different, and under the 3 different light energy densities, incubation of the cells with different HpD concentrations also resulted in significantly different cell survival rates (P<0.05). At the 4 low photosensitizer concentrations and with different light energy densities, the cell survival rates were similar (P>0.05), but the 4 higher photosensitizer concentrations resulted in significant difference in the cells survival (P<0.05). Correlation analysis showed that the intracellular photosensitizer concentration was positively correlated to the photosensitizer concentrations in cell incubation (r=0.997).</p><p><b>CONCLUSION</b>When the light source remains constant, the light energy density, the kinds of photosensitizers and their concentrations are the main factors affecting the Eca-109 cell-killing effect of PDT.</p>

Hematoporphyrin derivative-mediated photodynamic therapy for human nasopharyngeal carcinoma: a comparative study with CNE2 and C666-1 cell lines in vitro / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate biological effect of hematoporphyrin derivative (HpD) photodynamic therapy (PDT) on in vitro cultured nasopharyngeal carcinoma (NPC) cell lines CNE2 and C666-1.</p><p><b>METHODS</b>CNE2 and C666-1 cells cultured in vitro were incubated in a medium containing HpD at different concentrations (0.5, 1.0, 1.5, 2.0, 2.5, 3.0, 3.5, and 4.0 microg/ml) for 4 h followed by exposure to different light doses (2, 5, 10, and 20 J/cm2) using a diode laser at 630 nm with power density of 20 mW/cm2. After 24 h of incubation with HpD-PDT, the survival rate of CNE2 and C666-1 cells were analyzed by MTT assay.</p><p><b>RESULTS</b>HpD-PDT produced effective killing of CNE2 and C666-1 cells cultured in vitro, and the killing effects were positively correlated with HpD concentration and the irradiation dose. Exposure of CNE2 and C666-1 cells to irradiation dose of 20 J/cm2 resulted in the IC50 of 0.7 and 1.2 microg/ml, respectively (P<0.01). With the same HpD concentration and irradiation dose, the survival rate of C666-1 cells, however, was significantly higher than that of CNE2 cells (P<0.05).</p><p><b>CONCLUSION</b>HpD-PDT may result in effective killing of CNE2 and C666-1 cells cultured in vitro, although C666-1 cells are less sensitive to HpD-PDT than CNE2 cells.</p>

[Expression of CD66c (CEACM6) in adult acute leukemia and its significance].

OBJECTIVE: To explore the expression of CD66c (CEACM6) in adult acute leukemia and its significance. METHODS: Acute leukemia cell lines HL-60, K562, LCL721.221 and Jurkat were cultured in vitro. RT-PCR and multi-parameter flow cytometry were applied to analysis of CD66c mRNA and protein expression respectively in the cell lines and patient' s bone marrow leukemic cells. Cytogenetic analysis for 199 bone marrow samples from leukemia patients and Minimal Residual Disease (MRD) detection for 25 CD66c positive B lineage ALL were performed. RESULTS: (1) CD66c expression both on cell surface and in plasma were negative in all the cell lines. (2) Four of 127 AML (3.15%) (mainly of M2 and M4), and 28 of 79 ALL (35.44%) (all of B linage ALL) were CD66c positive the subtypes of the ALL being common B-ALL (20/54) and pre B-ALL (8/11) including 8 Ph + B-linage ALL. (3) Six-month relapse rate was significantly different between the MRD positive and negative patients. (4) CD66c mRNA was strongly expressed in B-linage ALL. For the cell lines, only the HL60 cells weakly expressed CD66c mRNA. CONCLUSION: CD66c expression could be a useful bio-marker for the MRD analysis in ALL, and is closely associated with its transcription level.

Preparation of hematoporphyrin-herceptin photoimmunoconjugate for photoimmunotherapy / 南方医科大学学报

<p><b>OBJECTIVE</b>To prepare photoimmunoconjugate of hematoporphyrin (HP) and herceptin, and study its killing and apoptosis-inducing effect on tumor cells BT-474.</p><p><b>METHODS</b>HP-herceptin photoimmunoconjugate was synthesized with EDCI as the condensator. After exposure of the cells to 630 nm laser, the killing effect of the conjugate and cell apoptosis were evaluated by MTT assay and flow cytometry.</p><p><b>RESULTS</b>Compared with free HP at equivalent dose, the immune reactivity, killing effect and the apoptosis-inducing effect of HP-herceptin immunoconjugate on BT-474 cells was enhanced (P<0.05).</p><p><b>CONCLUSION</b>The killing effect of HP-herceptin immunoconjugate is stronger than free HP on BT-474 cells.</p>

[Study on platelet activated state and platelet activated function in adults with acute leukemia].

To investigate the changes of platelet activated state and platelet activated function by trace whole blood flow cytometry (FCM), and to explore the mechanism of hemorrhage and infiltration in adults with acute leukemia, the expression percentage and changes of these expressions of CD62p and PAC-1 on platelet surface were determined by FCM of trace whole blood after platelet activated by ADP in patients with new diagnosed AL (group I), complete remission (CR, group II) and continuously complete remission (CCR, group III). Healthy adults were used as control group. The result showed that the expression of CD62p in group I and II was higher than that in control group, before and after platelet activated by ADP (P < 0.01). The expression of PAC-1 in group I was higher than that in control group (P < 0.01), the expression of PAC-1 in group II was lower than that in control group (P > 0.01), There was no significant difference in expression of CD62p and PAC-1 between group III and control group (P > 0.01), and no significant difference was found between AL group with megakaryocyte malignant pathological changes and AL group without megakaryocyte malignant pathological changes before platelet activated by ADP (P > 0.01). After platelet activated by ADP, the expression of PAC-1 in the former was lower than that in the latter (P < 0.01). It is concluded that (1) high level activated platelet in peripheral blood of AL patients show that interaction between activated platelet and leukemia cells can be one of reason resulting in widespread hemorrhage and infiltration AL patiens; (2) the decrease of number and activted function of platelet at the first stage of AL patients may be caused by malignant hyperplasia of leukemia cells and damage of megakaryopoiesis in bone marrow.

[Study on NB4 cell apoptosis induced by trichosanthin].

In order to study the influence of trichosanthin (TCS) on apoptosis and growth inhibition of human NB4 cells in vitro, the expression of annexin V and the change of DeltaPsim of NB4 cells induced by TCS was analyzed by FACS, and MTT assay was adopted to measure the growth inhibition ratio of NB4 cells treated with TCS. Apoptosis was assayed by agarose gel electrophoresis. The results showed the higher concentration of TCS and the longer the acting time, the stronger growth inhibition of NB4 cells. The expression of annexin V was positive, and the positive ratio was greatly enhanced with prolongation of acting time. DeltaPsim reduced gradually while the apoptosis cells increasing. DNA agarose gel electrophoresis showed a gradient, which confirmed that TCS could induce NB4 cells apoptosis. In conclusion, taken together, data show that TCS can inhibit NB4 growth in vitro, and induce apoptosis. Experiment provides an important evidence for application of TCS in clinical treatment of acute promyelocytic leukemia.