[Effects of a novel polyamine metabolic enzyme inhibitor SI-4650 on proliferation of colon cancer CT-26 cells and its mechanism].

OBJECTIVE: To investigate the effects of a novel polyamine metabolism enzyme inhibitor SI-4650 on autophagy and apoptosis of colon cancer CT-26 cells as well as their correlation. METHODS: CT-26 cells treated with 40, 80 µmol·L-1 SI-4650 alone or in combination with 3-MA were used as experimental group. CT-26 cells treated with 0 µmol·L-1 SI-4650 alone or in combination with 3-MA were used as control group. Chemiluminescence was used to analyze the effect of SI-4650 on spermine oxidase (SMO) and acetylpolyamine oxidase(APAO) activity. High performance liquid chromatography (HPLC) was performed to detect cellular polyamine content.The CCK8 method was used to detect the inhibitory effect of SI-4650 on proliferation of CT-26 cells. PI single-staining/flow cytometry (FCM) were used to analyze cell cycle. Western blot were used to analyze autophagy. Apoptosis was analyzed by PI/FITC-Annexin V double staining, JC-1 fluorescent probe and Fluo-3 AM calcium ion fluorescent probe combined with flow cytometry and Western blot. RESULTS: CCK8 assay showed that 24-,48-,72-hours treated with SI-4650 all could inhibit the proliferative activity of CT-26 cells in a dose- and time-dependent manner (P＜0.01) . The inhibition rate was 36.98% and 46.91% in 40 µmol·L-1 SI-4650 group and 80 µmol·L-1 SI-4650 group respectively. SI-4650 could significantly inhibit the activities of SMO and APAO interfere with polyamine metabolism and reduce the content of total polyamine in CT-26 cells (P＜0.01). SI-4650 could block CT-26 cells in G0/G1 phase, significantly reduce the number of cells in S phase(P＜0.01), and lead to a significant increase in the contents of autophagy-related Beclin-1, LC3-II in CT-26 cells(P＜0.01); At the same time, the concentration of calcium in CT-26 cells was increased, the mitochondrial membrane potential was decreased, the expressions of c-PARP and Bax were increased, the content of Bcl-2 was decreased, and the number of apoptotic cells was increased. After SI-4650 combined with autophagy inhibitor 3-MA treatment of CT-26 cells, the level of autophagy, the apoptosis-related protein, mitochondrial membrane potential and calcium ion concentration were decreased, and the number of apoptotic cells was decreased. CONCLUSION: SI-4650 has the pharmacological activity of killing colon cancer CT-26 cells, and its mechanism may be related to the interference of polyamine metabolism and induction of cell apoptosis and autophagy. In this process, autophagy is inhibited to block apoptosis, autophagy and apoptosis combined to kill tumor cells.

Efficacy of weekly paclitaxel for the treatment of advanced ovarian cancer: A protocol for systematic review and meta-analysis.

BACKGROUND: This study aims to assess the efficacy and safety of weekly paclitaxel (WP) for the treatment of advanced ovarian cancer (AOC). METHODS: This study will systematically search bibliographic databases (MEDLINE, EMBASE, Cochrane Library, Web of Science, CINAHL, PSYCINFO, Allied and Complementary Medicine Database, CNKI, WANGFANG, and Chinese Biomedical Literature Database) and other literature sources from inception to the March 1, 2020 without language and publication time limitations. Two authors will independently complete all literature selection, data collection, and study quality evaluation. Any disagreements will be solved by a third author through discussion. We will analyze data by RevMan V.5.3 software. RESULTS: This study will systematically generate a comprehensive summary on the efficacy and safety of WP for the treatment of AOC. CONCLUSION: This study may provide beneficial evidence of WP for the treatment of AOC. SYSTEMATIC REVIEW REGISTRATION: INPLASY202040193.

Molecular detection of novel circoviruses in ticks in northeastern China.

Novel circular single-stranded DNA (ssDNA) genomes have been found in various animals using high-throughput sequencing techniques. In this study, two circular ssDNA genomes were detected in adult ticks from northeastern China by Solexa sequencing and PCR. The two sequences shared a similar genomic organization to circoviruses, with genomes of 1936 bp (TiCV-1) and 1812 bp (TiCV-2), each including two major open read frames (ORFs), ORF1 and ORF2, encoding putative replicase and capsid proteins, respectively. The potential stem-loop structure of a circovirus was predicted in the intergenic region between the two ORFs. Sequence comparison showed that the genome of TiCV-2 was almost the same as that of TiCV-1, except for two deletions and several mutations, and they had a high identity of 71.3-72.9% with Raven circovirus. The infection rates of circoviruses were calculated by the maximum likelihood estimation as 3.2% (95% CI, 1.9-5.2%) for TiCV-1 in the investigated Haemaphysalis longicornis, and 1.2% (95% CI, 0.2-4.0%) for TiCV-2 in Ixodes crenulatus from Yichun of Heilongjiang Province. These results indicate that the two sequences are distantly related to known circovirus genomes and may represent novel species in the family Circoviridae.

7-O-geranylquercetin-induced autophagy contributes to apoptosis via ROS generation in human non-small cell lung cancer cells.

AIMS: To investigate the antitumor effects of 7-O-geranylquercetin (GQ), a novel O-alkylated derivative of quercetin, against non-small cell lung cancer (NSCLC) cell lines A549 and NCI-H1975 and the corresponding mechanisms. MAIN METHODS: Cell viability was assessed using MTT assay. The expression of proteins involved in apoptosis and autophagy was measured using western blotting. Besides, apoptosis was determined with DAPI staining, Annexin V-PI staining and transmission electron microscopy (TEM) assay, and autophagy was observed with TEM assay. Cell cycle and reactive oxygen species (ROS) level were detected using flow cytometry. KEY FINDINGS: GQ inhibited viability of A549 and NCI-H1975 cells in a dose- and time-dependent manner without apparent cytotoxicity to normal human lung fibroblast cells. GQ down-regulated the expression of apoptosis-related proteins pro-caspase 3 and Bcl-2, and up-regulated the expression of cleaved-PARP and Bax in A549 and NCI-H1975 cells. Meanwhile, GQ-induced cell apoptosis could be attenuated by caspase inhibitor Z-VAD-FMK. Besides, GQ induced autophagosome formation in A549 and NCI-H1975 cells, promoted the expression of autophagy-related proteins LC3-II and Beclin 1, and suppressed the expression of p62. Autophagy inhibition with chloroquine or Beclin 1 siRNA could effectively inhibit GQ-induced apoptosis. Furthermore, GQ treatment increased the generation of ROS, and ROS inhibitor N-acetylcysteine could reverse GQ-induced autophagy and apoptosis. Taken together, GQ could induce apoptosis and autophagy via ROS generation in A549 and NCI-H1975 cells, and GQ-induced autophagy contributed to apoptosis. SIGNIFICANCE: Our findings highlight that GQ is a promising anticancer agent for the treatment of lung cancer.

Biological activity studies of the novel glucagon-like peptide-1 derivative HJ07.

AIM: To identify the glucose lowering ability and chronic treatment effects of a novel coumarin-glucagon-like peptide-1 (GLP-1) conjugate HJ07. METHOD: A receptor activation experiment was performed in HEK 293 cells and the glucose lowering ability was evaluated with hypoglycemic duration and glucose stabilizing tests. Chronic treatment was performed by daily injection of exendin-4, saline, and HJ07. Body weight and HbA1c were measured every week, and an intraperitoneal glucose tolerance test was performed before treatment and after treatment. RESULTS: HJ07 showed well-preserved receptor activation efficacy. The hypoglycemic duration test showed that HJ07 possessed a long-acting, glucose-lowering effect and the glucose stabilizing test showed that the antihyperglycemic activity of HJ07 was still evident at a predetermined time (12 h) prior to the glucose challenge (0 h). The long time glucose-lowering effect of HJ07 was better than native GLP-1 and exendin-4. Furthermore, once daily injection of HJ07 to db/db mice achieved long-term beneficial effects on HbA1c lowering and glucose tolerance. CONCLUSION: The biological activity results of HJ07 suggest that HJ07 is a potential long-acting agent for the treatment of type 2 diabetes.

STAT3, p-STAT3 and HIF-1α are associated with vasculogenic mimicry and impact on survival in gastric adenocarcinoma.

Vasculogenic mimicry (VM) formation is important for invasion and metastasis of tumor cells in gastric adenocarcinoma (GAC). The present study aimed to investigate the association between signal transducer and activator of transcription-3 (STAT3), phosphor-STAT3 (p-STAT3), hypoxia-inducible factor-1α (HIF-1α) and VM formation in GAC, and discuss their clinical significance and correlation with the prognosis of patients with GAC. The expression levels of STAT3, p-STAT3, HIF-1α and VM were assessed in 60 cases of patients with GAC and 20 cases of patients with gastritis on tissue microarrays by immunohistochemical methods. The expression levels of STAT3, p-STAT3, HIF-1α and VM were higher in patients with GAC (particularly in poorly differentiated GAC) than in those with gastritis (P<0.05). The expression levels of STAT3, p-STAT3 and HIF-1α were higher in VM tissues compared with non-VM tissues (P<0.05). Positive correlations existed between STAT3, p-STAT3, HIF-1α and VM expression (P<0.05). The expression levels of STAT3, p-STAT3 and HIF-1α, VM, status of lymph node metastasis and tumor differentiation degree were associated with the overall survival time of patients with GAC (P<0.05). However, only p-STAT3 and VM expression were identified as the independent risk factors of GAC OS when analyzed with multivariate analysis. p-STAT3 and VM play a significant role in indicating the prognosis of patients with GAC. STAT3 activation may play a positive role in VM formation of GAC by the STAT3-p-STAT3-HIF-1α-VM effect axis.