[Effects of Methionine Restriction on Proliferation, Cell Cycle, and Apoptosis of Human Acute Leukemia Cells].

OBJECTIVE: To investigate the effects of methionine restriction on proliferation, cell cycle and apoptosis of human acute leukemia cells. METHODS: Cell Counting Kit-8 (CCK-8) assay was used to detect the effect of methionine restriction on HL-60 and Jurkat cells proliferation. The effect of methionine restriction on cell cycle of HL-60 and Jurkat cells was examined by PI staining. Annexin V-FITC / PI double staining was applied to detect apoptosis of HL-60 and Jurkat cells following methionine restriction. The expression of cell cycle-related proteins cyclin B1, CDC2 and apoptosis-related protein Bcl-2 was evaluated by Western blot assay. RESULTS: Methionine restriction significantly inhibited the proliferation of HL-60 and Jurkat cells in a time-dependent manner (HL-60: r =0.7773, Jurkat: r =0.8725), arrested the cells at G2/M phase (P < 0.001), and significantly induced apoptosis of HL-60 and Jurkat cells (HL-60: P < 0.001; Jurkat: P < 0.05). Furthermore, Western blot analysis demonstrated that methionine restriction significantly reduced the proteins expression of Cyclin B1 (P < 0.05), CDC2 (P < 0.01) and Bcl-2 (P < 0.001) in HL-60 and Jurkat cells. CONCLUSION: Acute leukemia cells HL-60 and Jurkat exhibit methionine dependence. Methionine restriction can significantly inhibit the proliferation, promote cell cycle arrest and induce apoptosis of HL-60 and Jurkat cells, which suggests that methionine restriction may be a potential therapeutic strategy for acute leukemia.

Incorporating a D-A-D-Type Benzothiadiazole Photosensitizer into MOFs for Photocatalytic Oxidation of Phenylsulfides and Benzylamines.

Oxidation and removal of highly toxic sulfides and amines are particularly important for environmental and human security but remain challenging. Here, incorporating an excellent photosensitizer, donor-acceptor-donor (D-A-D)-type 4,4'-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic (H2L), into metal-organic frameworks (MOFs) has been manifested to promote the charge separation, affording four three-dimensional (3D) MOFs (isostructural 1-Co/1-Zn with Co2/Zn2 units, and 2-Gd/2-Tb with Gd/Tb-cluster chains) as photocatalysts in the visible light-driven air-O2-mediated catalytic oxidation and removal of hazardous phenylsulfides and benzylamines. Impressively, structure-property correlation illustrated that the transition metal centers assembled in MOFs play an important role in the photocatalytic activity, and we can conclude that 1-Zn can be a robust heterogeneous catalyst possessing good light adsorption and fast charge separation in oxidation removal reactions of both benzylamines and phenylsulfides under visible light irradiation and room temperature with excellent activity/selectivity, stability, and reusability.

Formal (4+2) cycloaddition of azoalkenes with trifluoromethylimidoyl sulfoxonium ylides: synthesis of trifluoromethyl pyridazine derivatives.

CF3-substituted imidoyl sulfoxonium ylides (TFISYs) are extraordinarily versatile and powerful synthons for use in cyclization chemistry that affords diverse CF3-substituted N-heterocycles. We first reacted TFISYs as a two-atom synthon with readily available azoalkenes and then subjected the products to metal-free formal (4+2) cycloaddition chemistry. This protocol features mild conditions and broad substrate scope, is simple to operate, and provides highly functionalized trifluoromethylpyridazines that are widely found in bioactive molecules.

Three-dimensional digital measurement of the facet joint in normal individual and lumbar intervertebral disc herniation patients aged 13 - 18 years.

BACKGROUND: Lumbar facet joint is an important element of spinal "three-joint complex". Whether there is a relationship between strange structure of facet joint and adolescent lumbar disc herniation (ALDH) is nonetheless controversial, and the current research is mainly centered on adults. OBJECTIVE: To find out the normal lumbar facet joints between 13 and 18 years old to provide anatomical basis for early diagnosis and therapy of lumbar disc herniation. METHODS: CT imaging information of 32 sufferers with lumbar disc herniation aged from 13 to 18 years old in Inner Mongolia have been collected as the ALDH group, and 62 wholesome subjects in the equal period had been chosen as the normal group. Uncooked records of continuous scanning lumbar tomography pix were imported into MIMICS 21.0 for evaluation and size in DICOM format. The parameters include facet joint height, facet joint width, et al. RESULTS: 1. The left and right transverse angle of L5S1 segment in the ALDH group were (52.41 ± 9.2) ° and (55.99 ± 10.91) ° (P < 0.05), and the differences were statistically significant. The right side is larger than the left side. 2. Facet joint thickness in L3-L5 segment of the normal group was significantly higher than that of male (1.63 ± 0.32) mm than that of female (1.38 ± 0.25) mm; In 16-18 years old group, comparison of facet joint cross-sectional area was statistically significant (22.1 ± 3.04) mm2 in male than (18.92 ± 3.71) mm2 in female. 3. In comparison between normal and ALDH group, there was significant difference in L3-4 transverse angle (P < 0.05), L4-5 facet joint height and facet joint thickness (P < 0.05), L5S1 facet joint thickness and transverse angle (P < 0.05). CONCLUSION: When ALDH occurs in the L5S1 segment, there is a substantial difference between the left and right sides of the transverse angle, and there is a difference in the thickness and the facet joint cross-sectional area between males and females, which is generally larger in males than in females. Facet joint height is larger, transverse angle of left and right is asymmetric, inferior articular process is larger, and facet joint thickness is smaller can indicate that lumbar disc herniation is effortless to occur.

Risk factors for progression of interstitial lung disease in Sjögren's syndrome: a single-centered, retrospective study.

OBJECTIVE: To identify clinical characteristics and risk factors related to the progression of interstitial lung disease (ILD) in patients with primary Sjögren's syndrome (pSS). METHODS: In this single-centered, retrospective study, a total of 83 identified pSS-ILD patients with relatively complete clinical data were finally enrolled. Clinical symptoms, laboratory data, high-resolution computed tomography (HRCT), and pulmonary function test (PFT) results were collected. A logistic regression analysis was performed to determine the independent risk factors for ILD progression, and a nomogram was plotted to construct a predictive model. RESULTS: The prevalence of pSS-ILD in our study was 18.89%. Among the 83 enrolled patients, 32 (38.6%) underwent ILD progression. The characteristic features associated with the progression of ILD included male sex, non-sicca onset, reticular pattern on HRCT, higher levels of baseline lactic dehydrogenase (LDH), and low baseline forced vital capacity (FVC). The results of multivariate logistic regression indicated that LDH (OR 1.008, p = 0.030) was an independent risk factor for ILD progression, while sicca onset (OR 0.254, p = 0.044) and FVC (OR 0.952, p = 0.003) were protective factors for ILD progression. A simple predictive model for ILD progression in pSS was developed and validated. CONCLUSION: pSS patients with non-sicca onset, high baseline LDH level, and low baseline FVC were at higher risk of ILD progression.

A thermophilic chitinase 1602 from the marine bacterium Microbulbifer sp. BN3 and its high-level expression in Pichia pastoris.

Chitinases play an important role in many industrial processes, including the preparation of oligosaccharides with potential applications. In the present study, a 1,713 bp gene of Chi1602, derived from a marine bacterium Microbulbifer sp. BN3, encoding a GH18 family chitinase, was expressed at high levels in Pichia pastoris. Distinct from most of the marine chitinases, the recombinant chitinase 1602 exhibited maximal activity at 60 °C and over a broad pH range between 5.0 and 9.0, and was stable at 50 °C and over the pH range 4.0-9.0. The hydrolytic products derived from colloidal chitins comprised mainly (GlcNAc)2 and GlcNAc, indicating that rChi1602 is a GH18 processive chitinase in conformity with its hypothetical structure. However, rChi1602 showed traces of ß-N-acetylglucosaminidase activity on substrates such as powder chitin, chitosan, and ethylene glycol chitin. The thermophilic rChi1602, which manifests adaptation to a wide pH range and can be expressed at a high level in P. pastoris, is advantageous for applications in industrial processes.

PTH1-34 inhibited TNF-α expression and antagonized TNF-α-induced MMP13 expression in MIO mice.

This study aims to investigate the effects and mechanisms of parathyroid hormone [1-34] (PTH1-34) on TNF-α-stimulated mice chondrocytes, as well as cartilage from a meniscus injury induced osteoarthritis (MIO) mice model. The C57BL/6J mice received medial meniscectomy, and then administrated with PTH1-34. The results showed that PTH1-34 administration decreased secondary allodynia and the pain-related transcripts. The IHC, ELISA, Micro-CT imaging and histopathology analysis revealed the significantly improved subchondral plate thickness and bone porosity, the reduced pro-inflammatory cytokines in serum and joint fluid. In vitro, mice chondrocyte was treated with TNF-α or co-cultured with synovial cells. The results showed that TNF-α markedly upregulated the MMP13 expression, and the ERK1/2, NF-κB or PI3K signaling pathway inhibitors could reverse the induction effect of TNF-α on expression of MMP13 in chondrocytes. PTH1-34 alone has no effect on the expression of MMP13 and NF-κB signaling pathways, but the PTH1-34 could reverse the induction effect of TNF-α on MMP13 expression and NF-κB signaling pathway activation in chondrocytes. In addition, PTH1-34 administration inhibited the expression of TNF-α and MMP13, and chondrocyte viability, while the PKA repressor reversed the effect of PTH1-34 in chondrocytes co-cultured with synovial cells. In conclusion, PTH1-34 has an obvious analgesic and anti-inflammatory effect, inhibits the matrix synthesis and alleviates the progression of osteoarthritis. In vitro, PTH1-34 inhibited TNF-α expression and antagonized TNF-α-induced MMP13 expression via the PKA pathway and the NF-κB signaling pathways, respectively.

Diagnosing relapsing polychondritis remains a common challenge: experience from a Chinese retrospective cohort.

OBJECTIVE: The diagnosis of relapsing polychondritis (RP) is often mistaken or delayed. In this retrospective cohort, we aimed to unveil the causes responsible for such phenomenon, to determine the associated factors, and to compare diagnosis in clinical settings with the current diagnostic criteria. METHOD: Eighty-seven RP patients followed-up by rheumatologists from January 1, 2008, to October 31, 2018, were retrospectively analyzed. RESULTS: A total of 50 male and 37 female patients were included with a mean age of 45.9 ± 14.5 years. Ninety-three percent were initially admitted by non-rheumatologic specialists .Twenty-eight percent were correctly diagnosed, while 72% were misdiagnosed at the first visits, all by non-rheumatologic specialists. Patients admitted by non-rheumatologic specialists had increased odds of misdiagnosis (odds ratio [OR] = 1.3, 95% confidence interval [95% CI] 1.1-1.7, P = 0.000). Fifty-seven (65.5%) patients did not meet with Michet or Damiani criteria, with 16 (18.4%) patients diagnosed as partial RP and 41( 47.1%) patients diagnosed as limited RP. CONCLUSIONS: Incorrect and delayed diagnosis of RP is common in our cohort, and insufficient awareness of the disease in non-rheumatologic specialists at least partially contributes to this. It is imperative to revise the current criteria for early diagnosis.Key Points• Diagnosing relapsing polychondritis (RP) in early stage remains challenging after all these years, especially among non-rheumatologic specialists, indicating the importance of teaching non-rheumatologic specialists to improve their understanding of this rare disease.• Many RP patients did not fully meet with the current criteria, suggesting that revision of the current criteria is imperative for early diagnosis of this rare disease.

Local recurrence of sinonasal renal cell-like adenocarcinoma: A CARE compliant case report.

RATIONALE: Sinonasal renal cell-like adenocarcinoma (SNRCLA) is a very rare sino-nasal carcinoma. Because SNRCLA has the same morphological features as other clear cell carcinomas, and some of them also occurred in sinonasal part, it is necessary to differentiate SNRCLA from these tumors. PATIENT CONCERNS: A 42-year-old man presented with complaints of epistaxis for 1 day. The patient had undergone endoscopic resection of a neoplasm in the right nasal passage at another hospital 35 months before and was diagnosed with SNRCLA at that time, and did not receive any other adjuvant therapy. DIAGNOSES: The postoperative histopathological examination revealed a diagnosis of recurrent SNRCLA. INTERVENTIONS: The tumor was removed under nasal endoscopy. OUTCOMES: The patient was followed up for 2 months and recovered well without any complications. LESSONS: NSRCLA is a very rare tumor, and should be differentiated from other clear cell tumors including some salivary tumors and metastatic tumors of renal and thyroid.

Involvement of xanthine oxidase and paraoxonase 1 in the process of oxidative stress in nonalcoholic fatty liver disease.

Xanthine oxidase (XOD) and paraoxonase 1 (PON1) are important enzymes in redox reactions in vivo, and are predominantly synthesized by the liver. The aim of the present study was to investigate the redox state in nonalcoholic fatty liver disease, and determine the association between the activities of XOD and PON1 and the severity of NAFLD. Sprague­Dawley rats were randomly divided into control, model and α­lipoic acid (high and low dose) groups. The rats in the NAFLD model were induced by feeding a high fat diet for 12 weeks and the in vitro cell model of hepatocyte steatosis was induced by treating L­02 cells with oleic acid for 24 h. The body weight, liver function, lipid and oxidative stress indices, and histological features of the liver were examined in the rats. Compared with the control group, the rats in the NAFLD model group showed impaired liver function, lipid disorders and damage from oxidative stress. The serum activity of XOD increased significantly from the 4th week and was markedly higher, compared with that in the control group, reaching a peak in the 12th week. The activity of PON1 was negatively correlated with that of XOD. Compared with the control cells, the activity of XOD and levels of free­fatty acids were significantly higher, and the activity of PON1 was significantly lower in the NAFLD L­02 cell model. All the above indicators were significantly improved by treatment with the antioxidant, α­lipoic acid. The activities of XOD and PON1 may be promising as markers in a noninvasive approach for detecting the severity of NAFLD clinically. α­lipoic acid had protective effects on the NAFLD rats, and the potential mechanism may be associated with the inhibition of oxidative stress and lipid peroxidation.

A comparative adsorption study: 17ß-estradiol onto aerobic granular sludge and activated sludge.

Adsorption plays a significant role in removing hydrophobic 17ß-estradiol (E2) from wastewater. Batch experiments were conducted to compare the adsorption of E2 onto activated aerobic granular sludge (AGS) and activated sludge (AS), and features evaluated included the adsorption kinetics, thermodynamics, and influence of other environmental factors. By using a non-chemical wet-heat technique, both AGS and AS were treated to inactivated status. Then, after loading E2, the adsorption equilibrium capacity of the AGS was found to be greater than that of the AS at the same initial concentration of E2. Moreover, both the adsorption processes corresponded to a pseudo-second-order kinetic model; the adsorption rate constant of AGS was found to be higher and the half-adsorption time was shorter than that of AS. Next, evaluations of adsorption isotherms and thermodynamics indicated that the adsorption process was mainly a physical process. Lower temperatures facilitated a higher equilibrium adsorption capacity. However, the adsorption binding sites of AGS were distributed more uniformly at higher temperature, in contrast to the distribution found for AS. Finally, acidic conditions and an appropriate ionic strength (0.4 mol/L) were found to be particularly conducive to the adsorption process. Overall, the results showed that AGS has the potential to adsorb E2 with significant efficiency, thereby offering a new and more efficient means of treating E2 and trace oestrogens in wastewater.

Clinical utility of haptoglobin in combination with CEA, NSE and CYFRA21-1 for diagnosis of lung cancer.

PURPOSE: To investigate the clinical value in lung cancer of a combination of four serum tumor markers, haptoglobin (Hp), carcinoembryonic antigen (CEA), neuron specific enolase (NSE) as well as the cytokeratin 19 fragment (CYFRA21-1). MATERIALS AND METHODS: Serum Hp (with immune-turbidimetric method), CEA, NSE, CYFRA21-1 (with chemiluminescence method) level were assessed in 193 patients with lung cancer, 87 patients with benign lung disease and 150 healthy controls. Differences of expression were compared among groups, and joint effects of these tumor markers for the diagnosis of lung cancer were analyzed. RESULTS: Serum tumor marker levels in patients with lung cancer were obviously higher than those with benign lung disease and normal controls (p<0.01). The sensitivities of Hp, CEA, NSE and CYFRA21-1 were 43.5%, 40.9%, 23.3% and 41.5%, with specificities of 90.7%, 99.2%, 97.9% and 97.9%. Four tumor markers combined together could produce a positive detection rate of 85.0%, significantly higher than that of any single test. With squamous carcinomas, the positive detection rates with Hp and CYFRA21-1 were higher than that of other markers. In the adenocarcinoma case , the positive detection rate of CEA was higher than that of other markers. For small cell carcinomas, the positive detection rate of NSE was highest. The area under receiver operating characteristic curve (AUCROC) of Hp in squamous carcinoma (0.805) was higher than in adenocarcinoma (0.664) and small cell carcinoma (0.665). CONCLUSIONS: Hp can be used as a new serum tumor marker for lung cancer. Combination detection of Hp, CEA, NSE and CYFRA21-1 could significantly improve the sensitivity and specificity in diagnosis of lung cancer, and could be useful for pathological typing.

Synchronous poorly-differentiated neuroendocrine carcinoma and gastrointestinal stromal tumor of the stomach: a case report with immunohistochemical and molecular genetic analyses of KIT and PDGFRA.

Although the stomach is the most common location for gastrointestinal stromal tumor (GIST) with co-primary tumors, the synchronous appearance of a poorly differentiated neuroendocrine carcinoma (NEC) and GIST in the stomach is extremely rare. To the best of our knowledge, this is the first case of gastric GIST coexisting with gastric NEC to be reported in the literature. The current study reports the case of a 71-year-old male with gastric poorly differentiated NEC and GIST discovered incidentally during surgical treatment of the NEC. Immunohistochemistry analysis showed that the NEC tumor cells were positive for CK (cytokeratin), CD57, synaptophysin, chromogranin, CD117 (KIT protein), Dog-1 (discovered on GIST-1 protein) and CD34. The synchronous GIST immunophenotype showed positivity for CD117, Dog-1 and CD34 (100%), whereas staining for CK, SMA, desmin and S100 was negative. Ki-67 labeling of proliferating cells was 90% in NEC and 1% in GIST. An accurate diagnosis was confirmed by immunohistochemical findings. Furthermore, genetic analysis using PCR direct sequencing identified no mutations in the KIT (exons 9, 11, 13 and 17) and PDGFRA (exons 12 and 18) genes. The patient developed lymph node metastases and underwent cisplatin-based chemotherapy after the operation. This is the first documented case of synchronous gastric GIST and NEC with the examination of protein expression and gene mutations in KIT and PDGFRA, which will help to further understand the etiology and pathogenesis of NEC coexisting with GIST in a gastric location.

Effects of Cu2+ on morphological structure, functional groups, and elemental composition of aerobic granular sludge.

Aerobic granular sludge (AGS) is shaped by the self-immobilization of microorganisms. In this study, AGS was cultivated successively in a column sequencing batch reactor (SBR) with glucose and sodium acetate as the carbon sources. The shock-loading effects of varying the Cu2+ concentration (0.0, 1.0, 3.0, 5.0, or 10.0 mg/L) on the characteristics of aerobic granules were studied. The results show that Cu2+ has a toxic effect on the aerobic granules. Although the aerobic granules became increasingly loose as the Cu2+ concentration increased from 1.0 to 5.0 mg/L, their structural integrity was largely maintained. However, the aerobic granules disintegrated and their skeletons consisting of internal filamentous bacteria were exposed at the Cu2+ concentration of 10.0mg/L. The functional groups -NH2, -OH, -COOH, and C-N reacted with Cu2+. Ca, Fe, and P were the major trace elements observed in the AGS. With an increase in the Cu2+ concentration from 0.0 to 10.0 mg/L, the weight percentages of the essential elements Fe, Ca, Na, and K in the granules decreased from 23.98%, 24.64%, 3.86%, and 3.87% to 14.90%, 13.93%, 0%, and 0%, respectively, whereas the weight percentage of copper increased correspondingly from 0% to 35.43%. Cu2+ was exchanged with the essential metals and chelated by the nitrogen-containing functional groups (-NH2 or C-N) of the protein. These effects influenced the structural stability of the sludge.

Fate and removal of typical pharmaceuticals and personal care products by three different treatment processes.

The presence and distribution of typical of pharmaceuticals and personal care products (PPCPs), which comprise two types of polycyclic musks (PCMs) including Galaxolide (HHCB) and Tonalide (AHTN) as well as six types of estrogens containing estrone (E1), 17ß-estradiol (E2), estriol (E3), 17α-ethynylestradiol (EE2), diethylstilbestrol (DES), and bisphenol A (BPA), were investigated at two wastewater treatment plants (WWTPs) in Jiangsu, China. Only raw wastewater was treated in WWTP A while WWTP B was serving an urban-industrialized area. In the influent, the concentrations of EE2 (2193-4437ngL(-1)), E2 (1126-1170ngL(-1)), and DES (268-421ngL(-1)) were generally higher than the previously reported values, whereas the concentrations of HHCB (306-316ngL(-1)), E1 (29-129ngL(-1)), E3 (53ngL(-1)), and BPA (26-176ngL(-1)) were much lower than those reported in other previous studies. In addition, AHTN was not detected in either WWTP and E3 was not found in WWTP B. The detected processes including anaerobic/oxic process (A/O), combined orbal oxidation ditch process (C-orbal OD) and anaerobic/anoxic/anoxic/oxic membrane biological reactor (A/A/A/O-MBR) showed higher removal efficiencies for HHCB (67-71%) and EE2 (87%) than those in other previous studies. Besides, the total hydraulic retention time (HRT) ranged between 6.7 and 20.0h, sludge retention time (SRT) ranged between 8 and 23d, and water temperature ranged from 24.8 to 28.2°C. The removal efficiencies for estrogens in biological processes were related to the following factors: the level of hydrophobic estrogens, the type of removal process (C-orbal OD was consistently less efficient in removing estrogens than A/O and A/A/A/O-MBR), and a high SRT or HRT (A/A/A/O-MBR with higher SRT and HRT showed higher and more stable removal of hydrophobic estrogens).

[The short-term efficacy and safety of methotrexate plus low dose prednisone in patients with rheumatoid arthritis].

OBJECTIVE: To evaluate the clinical efficacy and safety of methotrexate (MTX) plus low dose glucocorticoid in the treatment of rheumatoid arthritis (RA) from the "target control" point of view. METHODS: Patients diagnosed as RA according to American College of Rheumatology (ACR)/European League against Rheumatism (EULAR) 2010 classification criteria were enrolled. All of the patients were prescribed with 15 mg/week MTX, 5 mg/week folic acid and prednisone (not exceeding 10 mg/day) orally. At week 0, 4, 12, disease activity and clinical efficacy were recorded. Co-primary assessment criterion was disease activity score (DAS28)-based on C-reactive protein (CRP). Secondary assessment criteria included EULAR response criteria, ACR response criteria, simplified disease activity index (SDAI) , clinical disease activity index (CDAI) . The tolerability and toxicity of MTX was recorded at week 4, 12. All patients were evaluated for the occurrence of adverse drug reactions associated with prednisone at week 12. RESULTS: A total of 76 patients were enrolled in the study. At week 4 and 12, 68 and 65 patients completed regular follow-up respectively. At week 12, there were 30 (46.2%), 9 (13.8%), 26 (40.0%) patients who met DAS28-CRP remission, low disease activity, middle and high disease activity criterion respectively. Three of nine patients who grouped in low disease activity after therapy were early or intermediate patients and didn't reach the target. Thus 36(55.4%) patients met the standard of target control. The percentage of patients who met the criteria of EULAR good response, the ACR criteria for 20% improvement (ACR20) , the ACR criteria for 50% improvement (ACR50), the ACR criteria for 70% improvement (ACR70) were 29.2%, 75.4%, 69.2%, 64.6%, respectively. The proportion of patients meeting the standard of treat to target using SDAI and CDAI were 76.9%, 58.5% respectively. The rate of liver injury, abdominal pain, abdominal distention and acid reflux, nausea were 11.8%, 4.4%, 4.4%, 2.9% respectively at week 4. At week 12, 4.6% of patients reported abdominal distention. There was only one patient (1.5%) each who complained of abdominal pain, nausea, loss of hair, varicella zoster virus infection and pulmonary infection at week 12. No serious adverse event was observed during the study. CONCLUSIONS: Based on the view of "target control", drug efficacy and safety, MTX plus low dose prednisone is still a useful therapeutic regimen for RA at present.

[Binding characteristics of interleukin 11 analogue-cyclic nonapeptide c(CGRRAGGSC) to human prostate cancer PC-3 cells: an in vitro study].

OBJECTIVE: To investigate the binding characteristics of interleukin 11 (IL-11) analogue-cyclic nonapeptide c(Cys-Gly-Arg-Arg-Ala-Gly-Gly-Ser-Cys) NH2 C30H54N16O10S2, c(CGRRAGGSC), and human prostate cancer PC-3 cells. METHODS: c(CGRRAGGSC) was labeled with fluorescent dye LSS670, and the location of LSS670-cyclic nonapeptide in the PC-3 cells was investigated by fluorescent microscopy. Flow cytometry was used to detect the fluorescence intensity of the in vitro binding of LSS670-c (CGRRAGGSC) to PC-3 cells and calculate its IC50 and Ki in competitive inhibition experiments. 99Tcm-DTPA-c(CGRRAGGSC) was synthesized by the reaction of 99mTcO4- with c(CGRRAGGSC). The binding characteristics of 99mTc-DTPA-c(CGRRAGGSC) and IL11R in the PC-3 cells were analyzed by radioreceptor assay. Bmax and Kd were calculated in saturability and reversibility experiments. RESULTS: The binding of LSS670-c(CGRRAGGSC) to the PC-3 cells showed the characteristics of saturability and concentration-time dependence. Unlabeled c(CGRRAGGSC) and LSS670-c(CGRRAGGSC) exhibited a competitive inhibition on the PC-3 cells (IC50 = [6.31 +/- 0.12] nmol/L, Ki = [2.11 +/- 0.14] nmol/L). Fluorescence was mainly distributed in the cell membrane (Kd = [0.32 +/- 0.02] nmol/L, Bmax = [754 +/- 34] fmol/mg pro). CONCLUSION: c (CGRRAGGSC) could bind PC-3 cells through a receptor-mediated pathway.