N-acetyl cysteine ameliorates aortic fibrosis by promoting M2 macrophage polarization in aging mice.

Background: Vascular fibrosis is a universal phenomenon associated with aging, and oxidative stress plays an important role in the genesis of vascular damage in line with the aging process. However, whether antioxidants can ameliorate vascular fibrosis remains unclear.Objectives: The present study was to determine antioxidant N-acetylcysteine (NAC) could ameliorates aortic fibrosis in aging wild-type C57BL/6 mice.Methods: The aortas were harvested from both 12-week and 60-week wild-type mice. The 60-week mice were treated with and without the NAC for 12 weeks starting at the age of 48 weeks. Hematoxylin and eosin (H&E) staining and Masson's trichrome staining of aortic samples were performed, and the levels of reactive oxygen species (ROS), RNA expression of GAPDH, TNF-α, MCP-1, IL-6, IL-10, IL-4, SIRT-1, SIRT-3, FOXO-1, and macrophage polarization were determined.Results: There is a positive relationship between collagen deposition and the M1/M2 macrophage ratio in the aortic wall of aged wild-type C57BL/6 mice. The higher collagen area percentage in the aortas of 60-week-old mice than in 12-week-old mice was reversed by NAC. NAC could not impact the total number of macrophages, but partly promoted M2 macrophage polarization. By performing qRT-PCR using aortic samples from these mice, we identified that SIRT-1, SIRT-3, FOXO-1 could be somehow responsible for aging-related fibrosis.Conclusions: NAC ameliorates aortic fibrosis in aging wild type mice partly by promoting M2 macrophage polarization.

Legionella septentrionalis sp. nov., isolated from aquatic environments in the northern PR China.

Four strains (km711T, km714, km542 and km524), representing a novel Legionella species, were isolated from aquatic environments in northern PR China. Cells were Gram-stain-negative, rod-shaped, microaerobic, motile and growth depended on l-cysteine. They grew at 25‒42 °C (optimum, 35‒37 °C) and could tolerate up to 1.5 % (w/v) NaCl (optimum, 0.5 %). The major fatty acids (>5 %) of the type strain km711T were C17 : 0 anteiso, C15 : 0 anteiso, iso-C16 : 0 and C16 : 1 ω7c and/or iso-C15 : 0 2OH. The pairwise comparison values were <96.1 % for 16S rRNA gene sequences, 23.3‒28.7 % interspecies variation for mip gene sequences, <93.6 % average nucleotide identity and <72.8 % average amino acid identity between these four strains and related type strains within the genus Legionella. The phylogenetic tree based on the four concatenated genes (16S rRNA, mip, rpoB and rnpB) and protein-concatamer tree based on concatenation of 21 protein markers both revealed that these four strains formed a separate phylogenetic branch cluster within the genus Legionella. The results of phenotypic and genotypic features suggest that these four strains represent a novel species of the genus Legionella, for which the name Legionella septentrionalis sp. nov. is proposed (type strain km711T=KCTC 15655T=NBRC 113219T).

Sorting nexin-1 is a candidate tumor suppressor and potential prognostic marker in gastric cancer.

Sorting nexin-1 (SNX1) is an important functional protein in cell endocytosis, efflux, protein sorting, cell signal transduction, etc; however, the expression, the role and clinical relevance of SNX1 have not been investigated in gastric cancer (GC). In this study, we first performed a bioinformatics investigation using the data obtained from The Cancer Genome Atlas (TCGA) database. The result showed that SNX1 mRNA levels were significantly lower in GC tissues than in paracancerous tissues. In a study of 150 cases of GC, including 60 cases with paired paracancerous and cancer tissues and 90 cases with detailed follow-up information, SNX1 expression was analyzed by immunohistochemistry. Our study on paired paracancerous and cancer tissues showed that SNX1 protein expression remarkably decreased in GC tissues (50/60, 83.33%). A study on 90 patients with detailed follow-up information showed that tumors with higher SNX1 protein level were correlated with better clinicopathologic stages (p = 0.0285), nodal status (p = 0.0286), smaller tumor sizes (p = 0.0294) and a better survival rate in patients with GC (p = 0.0245). Univariate analysis of the 90 patients with GC showed that low-level SNX1 was significantly correlated with decreased overall survival of GC patients (p = 0.008), and associated with a relatively higher cumulative hazard of death. Exogenous expression of SNX1 inhibited the growth, migration, invasion and promoted the apoptosis and enhanced the sensitivity of GC cells to the chemotherapeutic drug 5-Fluorouracil (5-Fu) in vitro, while knockdown of SNX1 by short hairpin RNA (shRNA) significantly promoted the growth, migration, invasion and reduced the apoptosis and the sensitivity of GC cells to 5-Fu. SNX1 also showed to influence the levels of epithelial-mesenchymal transition markers including Vimentin, Snail, and E-cadherin in GC cells in vitro. Taken together, we propose here that SNX1 serves as a tumor suppressor and prognostic marker that reduces tumor cell malignancy for GC.

Depression promotes prostate cancer invasion and metastasis via a sympathetic-cAMP-FAK signaling pathway.

Depression drives cancer progression and induces poor clinical outcome. However, the mechanisms underlying depression and cancer outcomes are unclear. In this work, we investigated 98 prostate cancer patients and found that patients with high score of psychological depression were correlated with tumor invasion and metastasis. We found focal adhesion kinase (FAK) was increased in cancer patients with metastatic features and high score of depression. FAK knockdown completely blocked depression-promoted tumor invasion in orthotopic transplantation tumors. In Hi-myc mice and a murine model of depression, sympathetic activation was detected in the prostate tissue. Further we showed that FAK activation was dependent on a cAMP-PKA signaling pathway. Our results demonstrated that the activation of a sympathetic-FAK signaling pathway in prostate cancer patients with high degrees of depression facilitates tumor invasion. We suggest that blocking ß2AR with propranolol or inhibiting FAK activation with PF562 271 may be novel strategies for depressed patients with invasive prostate cancer.

Evolution of methicillin-resistant Staphylococcus aureus: Evidence of positive selection in a penicillin-binding protein (PBP) 2a coding gene mecA.

Methicillin-resistant Staphylococcus aureus (S. aureus) (MRSA) represents more and more S. aureus infections. MecA, the novel coding gene of penicillin-binding protein (PBP) 2a of MRSA, is the key resistance factor of ß-lactam, but little is known about the evolution of this gene. Given the crucial role of mecA in S. aureus physiology and ß-lactam resistance, the selective forces may contribute to adaptation of the bacteria to the special environments such as its host or antibiotics. To understand the evolution of this gene, we screened GenBank database and analyzed mecA of 249 S. aureus strains. Twenty-nine unique alleles with 26 unique amino acid sequences were identified. Phylogenetic analysis showed three main groups of mecA in the global S. aureus strains. Analysis of these alleles using codon-substitution models (M8, M3, and M2a) and likelihood ratio tests (LRTs) of the codeML package and a random-effects likelihood (REL) method of HyPhy package for the site-specific ratio of nonsynonymous to synonymous substitution rates suggested that fourteen sites in the allosteric domain of PBP2a have been subjected to strong positive selection pressure. Mutations of two positive selection sites (N146K and E239K) were reported to be essential for ceftaroline- or L-695, 256-resistant. Further study indicated that the positive selection pressure might be more likely related to the host's inflammatory or immune response during S. aureus infection. Our studies provide the first evidence of positive Darwinian selection in the mecA of S. aureus, contributing to a better understanding of the adaptive mechanism of this bacterium.

Molecular typing of Legionella pneumophila isolates from environmental water samples and clinical samples using a five-gene sequence typing and standard Sequence-Based Typing.

Inadequate discriminatory power to distinguish between L. pneumophila isolates, especially those belonging to disease-related prevalent sequence types (STs) such as ST1, ST36 and ST47, is an issue of SBT scheme. In this study, we developed a multilocus sequence typing (MLST) scheme based on two non-virulence loci (trpA, cca) and three virulence loci (icmK, lspE, lssD), to genotype 110 L. pneumophila isolates from various natural and artificial water sources in Guangdong province of China, and compared with the SBT. The isolates were assigned to 33 STs of the SBT and 91 new sequence types (nSTs) of the MLST. The indices of discrimination (IODs) of SBT and MLST were 0.920 and 0.985, respectively. Maximum likelihood trees of the concatenated SBT and MLST sequences both showed distinct phylogenetic relationships between the isolates from the two environments. More intragenic recombinations were detected in nSTs than in STs, and they were both more abundant in natural water isolates. We found out the MLST had a high discriminatory ability for the disease-associated ST1 isolates: 22 ST1 isolates were assigned to 19 nSTs. Furthermore, we assayed the discrimination of the MLST for 29 reference strains (19 clinical and 10 environmental). The clinical strains were assigned to eight STs and ten nSTs. The MLST could also subtype the prevalent clinical ST36 or ST47 strains: eight ST36 strains were subtyped into three nSTs and two ST47 strains were subtyped into two nSTs. We found different distribution patterns of nSTs between the environmental and clinical ST36 isolates, and between the outbreak clinical ST36 isolates and the sporadic clinical ST36 isolates. These results together revealed the MLST scheme could be used as part of a typing scheme that increased discrimination when necessary.

Molecular evolution of virulence genes and non-virulence genes in clinical, natural and artificial environmental Legionella pneumophila isolates.

BACKGROUND: L. pneumophila is the main causative agent of Legionnaires' disease. Free-living amoeba in natural aquatic environments is the reservoir and shelter for L. pneumophila. From natural water sources, L. pneumophila can colonize artificial environments such as cooling towers and hot-water systems, and then spread in aerosols, infecting the susceptible person. Therefore, molecular phylogeny and genetic variability of L. pneumophila from different sources (natural water, artificial water, and human lung tissue) might be distinct because of the selection pressure in different environments. Several studies researched genetic differences between L. pneumophila clinical isolates and environmental isolates at the nucleotide sequence level. These reports mainly focused on the analysis of virulence genes, and rarely distinguished artificial and natural isolates. METHODS: We have used 139 L. pneumophila isolates to study their genetic variability and molecular phylogeny. These isolates include 51 artificial isolates, 59 natural isolates, and 29 clinical isolates. The nucleotide sequences of two representative non-virulence (NV) genes (trpA, cca) and three representative virulence genes (icmK, lspE, lssD) were obtained using PCR and DNA sequencing and were analyzed. RESULTS: Levels of genetic variability including haplotypes, haplotype diversity, nucleotide diversity, nucleotide difference and the total number of mutations in the virulence loci were higher in the natural isolates. In contrast, levels of genetic variability including polymorphic sites, theta from polymorphic sites and the total number of mutations in the NV loci were higher in clinical isolates. A phylogenetic analysis of each individual gene tree showed three to six main groups, but not comprising the same L. pneumophila isolates. We detected recombination events in every virulence loci of natural isolates, but only detected them in the cca locus of clinical isolates. Neutrality tests showed that variations in the virulence genes of clinical and environmental isolates were under neutral evolution. TrpA and cca loci of clinical isolates showed significantly negative values of Tajima's D, Fu and Li's D* and F*, suggesting the presence of negative selection in NV genes of clinical isolates. DISCUSSION: Our findingsreinforced the point that the natural environments were the primary training place for L. pneumophila virulence, and intragenic recombination was an important strategy in the adaptive evolution of virulence gene. Our study also suggested the selection pressure had unevenly affected these genes and contributed to the different evolutionary patterns existed between NV genes and virulence genes. This work provides clues for future work on population-level and genetics-level questions about ecology and molecular evolution of L. pneumophila, as well as genetic differences of NV genes and virulence genes between this host-range pathogen with different lifestyles.

STEMI could be the primary presentation of acute aortic dissection.

BACKGROUND: Stanford type A aortic dissection (TAAD) may lead to coronary artery occlusion and malfunction. However, TAAD manifesting as acute ST-segment elevation myocardial infarction (STEMI) has not been studied. In the present study, we reported 8 TAAD cases with STEMI as the primary presentation, and analyzed their clinical characteristics and outcome. METHODS: The records were reviewed for patients admitted to the large comprehensive university hospital for PCI due to STEMI from January 1, 2002 to January 1, 2017. RESULTS: The incidence of STEMI secondary to TAAD in our center was 0.51% (8/1,576). A total of 5 patients underwent urgent coronary angiography (CAG) without awareness of TAAD. Compression at the ostium of right coronary artery (RCA) was found in 2 patients, dissected flap of RCA in 1 patient, and heterogeneous filling and false lumen in RCA in 1 patient. Three of these 5 patients received surgery and survived. One patient accepted urgent RCA stenting because of cardiogenic shock and died after refusal of surgical therapy and failure of medical treatment. Another 2 patients received thrombolytic therapy died prior to CAG. Thus, the total in-hospital mortality was 37.5% (3/8). CONCLUSIONS: TAAD presenting as STEMI was a rare condition that predominantly involved RCA. A quick and correct clinical diagnosis of STEMI caused by TAAD prior to invasive procedure would be important. Urgent CAG without awareness of TAAD could provide important information for a timely diagnosis. High level of suspicion and awareness is the key to establishing the diagnosis and achieving optimal clinical outcome.

Transurethral assistant transumbilical laparoendoscopic single-site radical prostatectomy.

The laparoendoscopic single-site (LESS) technique is the latest technical innovation in laparoscopic surgery to undergo exponential development in urology. This study undertaken to illustrate our initial experience LESS radical prostatectomy (RP) and analyze early outcomes. Nineteen patients diagnosed with prostate cancer underwent LESS-RP in our institute. The patients were divided into two groups: conventional LESS and transurethral assistant LESS. Preoperative, perioperative, postoperative, pathologic, and functional outcomes data were assessed. With the help of a transurethral assistant, the mean operation and anastomosis time were decreased markedly. No focal positive margins were encountered. No prostate-specific antigen recurrence was detected 1 month postoperatively. Complete continence recovery (no pad) was observed in 32% of the patients at 1 month after the operation. No intraoperative and postoperative complications were reported. LESS-RP is a feasible and effective surgical procedure for treatment of prostate cancer. Moreover, transurethral assistant LESS could reduce the difficulty of LESS-RP and shorten the operation time.

[Chinese medicinal compound CFF-1 induces the apoptosis and cycle-arrest of prostate cancer cells via the PI3K/AKT/FOXO1 signaling pathway].

OBJECTIVE: To explore the apoptosis-inducing effect of the Chinese medicinal compound CFF-1 on prostate cancer cells and its related molecular mechanisms. METHODS: Normal prostate WPMY-1 cells and prostate cancer LNCaP, CWR22Rv1, PC3 and DU145 cells were treated in dehydrated alcohol with CFF-1 at 0, 2, 5, or 10 mg/ml for 24 hours. Then the viability of the prostate cells was detected by morphological observation, MTT and CCK-8 assay, nuclear condensation and disruption measured by DAPI staining, the cell cycle and apoptosis calculated by flow cytometry, the activity of the PI3K/AKT/FOXO1 signaling pathway and the expressions of its downstream apoptosis- and cycle-related proteins determined by Western blot. RESULTS: CFF-1 significantly arrested the cell cycle in the G1 phase, decreased the cell viability and increased the nuclear condensation and disruption in a dose-dependent manner, and elevated the apoptosis rate of prostate cancer cells. At the molecular level, CFF-1 dose-dependently reduced the activity of the PI3K/AKT signaling pathway and phosphorylation of the FOXO1 protein, increased the transcription activity of FOXO1, and eventually regulated the expressions of cell apoptosis- and cycle-related genes. CONCLUSIONS: The Chinese medicinal compound CFF-1 can significantly inhibit the growth, arrest the cycle, and induce the apoptosis of prostate cancer cells by decreasing the activity of the PI3K/AKT/FOXO1 signaling pathway, which suggests its potential clinical application value in the treatment of prostate cancer.

[Clinical efficacy of integrated traditional Chinese and Western medicine for castration-resistant prostate cancer].

OBJECTIVE: To investigate the clinical effects of integrated traditional Chinese and Western medicine in the treatment of castration-resistant prostate cancer (CRPC). METHODS: A total of 54 CRPC patients were randomly divided into a control and a trial group, all treated by endocrine therapy (oral Bicalutamide at 50 mg per d plus subcutaneous injection of Goserelin at 3.6 mg once every 4 wk) and chemotherapy (intravenous injection of Docetaxel at 75 mg/m2 once every 3 wk plus oral Prednisone at 5 mg bid), while the latter group by Fuyang Huayu Prescription (a Traditional Chinese Medicine ï¼»TCMï¼½ prescription for tonifying yang and dispersing blood stasis) in addition, for a course of 24 weeks. Comparisons were made between the two groups of patients in the level of serum prostate-specific antigen (PSA), Karnofsky physical condition scores, function assessment of cancer therapy-prostate (FACT-P) scores, and TCM symptoms scores before and after 12 or 24 weeks of treatment. RESULTS: Compared with the baseline, the serum PSA level was significantly decreased after 12 weeks of treatment both in the control (ï¼»25.9 ± 39.3ï¼½ vs ï¼»20.0 ± 21.1ï¼½ µg/L, P <0.05) and in the trial group (ï¼»22.1 ± 33.9ï¼½ vs ï¼»17.9 ± 19.1ï¼½ µg/L, P <0.05), with no statistically significant differences between the two groups (P >0.05). At 24 weeks, however, the PSA levels in the control and trial groups were slightly increased to (23.1 ± 28.4) and (19.6 ± 23.5) µg/L, respectively, with no statistically significant differences in between (P >0.05). Karnofsky, FACT-P and TCM symptoms scores were all markedly improved in the trial group after 12 weeks of treatment (P <0.05) and remained stable at 24 weeks, but not in the control group either at 12 or at 24 weeks (P >0.05). CONCLUSIONS: TCM Fuyang Huayu Prescription combined with endocrine therapy and chemotherapy is effective for CRPC.

[Updated treatments of castration-resistant prostate cancer].

The diagnosis and treatment of prostate cancer are being improved due to the popularized screening of prostate specific antigen. Advanced prostate cancer, in spite of its response to androgen deprivation therapy, may finally develop into castration-resistant prostate cancer (CRPC) and shorten the overall survival of the patients. Many efforts have been made by worldwide researchers for new approaches to the management of CRPC, including new hormonal therapy, cytotoxic chemotherapy, immunotherapy, and bone metastasis-targeted therapy. This paper reviews the emerging agents undergoing clinical evaluation and drugs that have received approval for the treatment of CRPC in order to provide doctors and patients with more treatment options for CRPC and improve the overall survival rate and quality of life of the patients.

Targeting single-nucleotide polymorphisms in the 16S rRNA gene to detect and differentiate Legionella pneumophila and non-Legionella pneumophila species.

A PCR-based method targeting single-nucleotide polymorphisms (SNPs) in the 16S rRNA gene was developed for differential identification of Legionella pneumophila and non-Legionella pneumophila. Based on the bioinformatics analysis for 176 Legionella 16S rRNA gene fragments of 56 different Legionella species, a set of SNPs, A(628)C(629) was found to be highly specific to L. pneumophila strains. A multiplex assay was designed that was able to distinguish sites with limited sequence heterogeneity between L. pneumophila and non-L. pneumophila in the targeted 16S rRNA gene. The assay amplified a 261-bp amplicon for Legionella spp. and a set of 203- and 97-bp amplicons only specific to L. pneumophila species. Among 49 ATCC strains and 284 Legionella isolates from environmental water and clinical samples, 100 % of L. pneumophila and non-L. pneumophila strains were correctly identified and differentiated by this assay. The assay presents a more rapid, sensitive and alternative method to the currently available PCR-sequencing detection and differentiation method.

Different distribution patterns of ten virulence genes in Legionella reference strains and strains isolated from environmental water and patients.

Virulence genes are distinct regions of DNA which are present in the genome of pathogenic bacteria and absent in nonpathogenic strains of the same or related species. Virulence genes are frequently associated with bacterial pathogenicity in genus Legionella. In the present study, an assay was performed to detect ten virulence genes, including iraA, iraB, lvrA, lvrB, lvhD, cpxR, cpxA, dotA, icmC and icmD in different pathogenicity islands of 47 Legionella reference strains, 235 environmental strains isolated from water, and 4 clinical strains isolated from the lung tissue of pneumonia patients. The distribution frequencies of these genes in reference or/and environmental L. pneumophila strains were much higher than those in reference non-L. pneumophila or/and environmental non-L. pneumophila strains, respectively. L. pneumophila clinical strains also maintained higher frequencies of these genes compared to four other types of Legionella strains. Distribution frequencies of these genes in reference L. pneumophila strains were similar to those in environmental L. pneumophila strains. In contrast, environmental non-L. pneumophila maintained higher frequencies of these genes compared to those found in reference non-L. pneumophila strains. This study illustrates the association of virulence genes with Legionella pathogenicity and reveals the possible virulence evolution of non-L. pneumophia strains isolated from environmental water.

[Transurethral transumbilical laparoendoscopic single-site surgery for radical prostatectomy].

OBJECTIVE: To investigate the feasibility and advantages of transurethral transumbilical laparoendoscopic single-site surgery (TU-LESS) for radical prostatectomy. METHODS: Five patients with prostate cancer underwent TU-LESS for radical prostatectomy, with a four-channel single-port device inserted into a 2. 5 cm periumbilical incision and another placed through the urethra, followed by analysis of the perioperative data. RESULTS: All the operations were successfully accomplished, with neither conversion to open surgery nor additional channel. The mean operation time, intraoperative blood loss, and postoperative hospital stay were 168 min, 120 ml, and 15 d, respectively. No severe perioperative complications were observed. TNM stage classification manifested T2cN0M0 in 2 cases and T2bN0M0 in the other 3. Postoperative pathology showed no negative surgical margins in any of the cases. CONCLUSION: TU-LESS is safe and feasible for radical prostatectomy and can reduce the complication of low urinary tract surgery by single-site laparoendoscopy.

[Indirubin inhibits the proliferation of prostate cancer PC-3 cells].

OBJECTIVE: To explore the antitumoral effect of indirubin on androgen-independent prostate cancer PC-3 cells and its possible mechanisms. METHODS: We measured the inhibitory effect of indirubin on the proliferation of prostate cancer PC-3 cells using MTT assay, detected their cell cycles by flow cytometry, and determined the expressions of the cell cycle regulatory protein cyclin D1 and its related downstream gene c-myc by Western blot. RESULTS: The viability of the PC-3 cells was significantly decreased by indirubin in a concentration-dependent manner, reduced to 52. 2% and 13. 6% at 5 and 10 µmol/L, respectively. The cell cycle of the PC-3 cells was markedly inhibited by indirubin at 5 µmol/L, with the cells remarkably increased in the G0 and G1 phases and decreased in the S and G2/M phases. Meanwhile, indirubin also inhibited the expressions of cyclin D1 and c-myc in the Wnt signaling pathway. CONCLUSION: Indirubin can suppress the proliferation of androgen-independent prostate cancer PC-3 cells, which may be associated with its inhibitory effect on the cell cycle and Wnt signaling pathway.

A Simple Emergency Prediction Tool for Acute Aortic Dissection.

BACKGROUND: A simple emergency risk prediction tool should be developed for clinicians to quickly identify the prognosis of patients with acute aortic dissection. METHODS: We enrolled 280 patients with acute aortic dissection admitted to emergency department between May 2010 and February 2013. Multivariate logistic regression analysis was performed to identify independent predictors of in-hospital death. RESULTS: The in-hospital mortality of our patients with acute aortic dissection was 32.5%, in-hospital deaths with surgery less than the survived (34.1% VS 54.5%). Multivariate analysis identified that age (≥65 years old), Type A, blood pressure (mean systolic blood pressure ≤ 90 mmHg), neutrophil percentage (≥ 80%) and serum D-dimer (≥ 5.0 mg/L) were significant predictors of death. With the simple emergency risk prediction tool, scores of all in-hospital deaths were ≥ 3, whereas almost all of the survivors (97.9%) had scores < 15. A score of 10 offered the best threshold value, with the highest sensitivity (81.3%) and specificity (86.8%). CONCLUSIONS: The in-hospital mortality rate of patients with acute aortic dissection is high and can be predicted. Early surgery would be beneficial for in-hospital survive. This tool should be available for clinicians in the emergency department to quickly identify the prognosis of patients with acute aortic dissection.

Altered lymphocyte counts in a pediatric patient with H5N1 infection.

Flow cytometry was used to analyze the changes in lymphocyte subsets in the youngest child with avian influenza in China. During the early stage, the absolute CD3 count was 62.9% (lower limit of normal), the CD8 count was 32.5% (slightly higher than normal), and the CD4 count was 28.6% (lower than normal). The CD4/CD8 ratio was also decreased (0.88). The natural killer (CD3CD1656) cell count was 4.9% (lower than normal). During the convalescent stage, the CD4 count and the CD4/CD8 ratio returned to normal. The CD3CD1656 count increased from its value at the early stage of the disease.

[Quercetin induces the apoptosis of human PC-3 cells].

OBJECTIVE: To study the effect of quercetin on the apoptosis of human PC-3 cells. METHODS: Human PC-3 cells were cultured in vitro and then treated with quercetin at the concentrations of 50, 100, 150, 200 and 250 micromol/L. The inhibition rate of quercetin on the PC-3 cells was detected by MTT, the apoptosis of the cells determined by flow cytometry, and the changes of the cellular ultramicrostructure observed by transmission electron microscopy. RESULTS: Quercetin markedly inhibited the proliferation of PC-3 cells in vitro in a time- and dose-dependent manner. Its inhibition rates were (3.01 +/- 1.32)%, (4.84 +/- 1.73)%, (20.35 +/- 1.30)%, (16.78 +/- 1.89)% and (27.25 +/- 4.01)% at 24 hours, and (10.18 +/- 1.16)%, (6.22 +/- 0.04)%, (24.29 +/- 4.19)%, (22.4 +/- 4.26)% and (41.42 +/- 5.43)% at 48 hours in the 50, 100, 150, 200 and 250 micromol/L groups, respectively, with statistical significance at the concentration of > 150 micromol/L (P < 0.05). Flow cytometry showed that the apoptosis of PC-3 cells was increased with the elevated concentration and prolonged time of Quercetin treatment, (19.10 +/- 0.28)% and (26.55 +/- 0.78)% at 24 hours, and (27.65 +/- 1.06)% and (38.30 +/- 5.96)% at 48 hours in the 150 and 200 micromol/L groups, respectively (P < 0.05). Typical changes in the morphology of the cells were observed under the transmission electron microscope. CONCLUSION: Quercetin can inhibit the proliferation and induce the apoptosis of human PC-3 cells, but its action mechanism remains to be further investigated.