Association between vitamin B2 intake and prostate-specific antigen in American men: 2003-2010 National Health and Nutrition Examination Survey.

BACKGROUND: Accumulating evidence suggests a pivotal role of vitamin B2 in the pathogenesis and progression of prostate cancer (PCa). Vitamin B2 intake has been postulated to modulate the screening rate for PCa by altering the concentration of prostate-specific antigen(PSA). However, the relationship between vitamin B2 and PSA remains indeterminate. Hence, we conducted a comprehensive evaluation of the association between vitamin B2 intake and PSA levels, utilizing data from the National Health and Nutrition Examination Survey (NHANES) database. METHODS: From a pool of 20,371 participants in the NHANES survey conducted between 2003 and 2010, a cohort of 2,323 participants was selected for the present study. The male participants were classified into four distinct groups based on their levels of vitamin B2 intake. We employed a multiple linear regression model and a non-parametric regression method to investigate the relationship between vitamin B2 and PSA levels. RESULTS: The study cohort comprised of 2,323 participants with a mean age of 54.95 years (± 11.73). Our findings revealed a statistically significant inverse correlation between vitamin B2 intake (mg) and PSA levels, with a reduction of 0.13 ng/ml PSA concentration for every unit increase in vitamin B2 intake. Furthermore, we employed a fully adjusted model to construct a smooth curve to explore the possible linear relationship between vitamin B2 intake and PSA concentration. CONCLUSIONS: Our study in American men has unveiled a notable inverse association between vitamin B2 intake and PSA levels, potentially posing a challenge for the identification of asymptomatic prostate cancer. Specifically, our findings suggest that individuals with higher vitamin B2 intake may be at a greater risk of being diagnosed with advanced prostate cancer in the future, possibly indicating a detection bias. These results may offer a novel explanation for the observed positive correlation between vitamin B2 intake and prostate cancer.

Elevated levels of ß2-microglobulin in cerebrospinal fluid in adult patients with viral encephalitis/meningitis.

BACKGROUND: Increased cerebrospinal fluid (CSF) ß2-microglobulin (ß2-MG) values are attributed to immune activation, lymphoid cell turnover and release of tissue destruction in the central nervous system (CNS). We investigated plasma and CSF ß2-MG levels in adult patients with viral encephalitis/meningitis and their correlations with clinical parameters. METHOD: CSF samples from 26 patients with viral encephalitis/meningitis were collected. Moreover, 24 CSF samples from patients with non-inflammatory neurological disorders (NIND) as controls were collected. Plasma samples from 22 enrolled patients and 20 healthy individuals were collected. The ß2-MG levels were measured by immunoturbidimetry on an automatic biochemical analyzer. Clinical data were extracted from an electronic patient documentation system. RESULT: CSF levels of ß2-MG, adenosine deaminase (ADA), white blood cell (WBC), lactate dehydrogenase (LDH), protein and lactate were significantly increased in patients with viral encephalitis/meningitis respectively (p < 0.001, p < 0.001, p < 0.001, p = 0.001, p < 0.001, p = 0.013). In contrast, no statistically significant difference was found in plasma levels of ß2-MG. Furthermore, CSF levels of ß2-MG were weakly correlated with WBC (r = 0.426, p = 0.030), lymphocyte percentage (r = 0.599, p = 0.018), ADA (r = 0.545, p = 0.004) and LDH (r = 0.414, p = 0.036), but not with lactate (r = 0.381, p = 0.055), protein (r = 0.179, p = 0.381) and plasma levels of ß2-MG (r = -0.156, p = 0.537) in viral encephalitis/meningitis patients. CONCLUSION: CSF ß2-MG may be a potential inflammatory marker for viral encephalitis/meningitis in adult patients diagnosed with viral encephalitis/meningitis.

The Function and Modification of Human Defensin 5.

The antibacterial and antiviral functions of human defensin 5 lay the foundation for its role as a core host protective component. In addition, HD5 also has the function of inhibiting tumor proliferation and immune regulation. However, everything has two sides; cytotoxic and proinflammatory properties may exist, while HD5 performs physiological functions. Accordingly, the modification and engineering of HD5 are particularly important. Therefore, this review summarizes the role of HD5 in various aspects of host defense, as well as modification of HD5 to ameliorate the biological activity, with a view to promoting the clinical use of HD5.

Serum irisin levels in patients with myasthenia gravis.

OBJECTIVE: Myasthenia gravis (MG) is an autoimmune disorder whose main symptoms are muscle weakness and fatigue. Irisin is a novel skeletal muscle-derived myokine participating in several physiological and pathological processes. The initial objective of the project was to explore serum levels of irisin in patients with MG, as well as its correlation with disease severity. METHODS: We retrospectively evaluated serum levels of irisin in 77 MG patients and 57 healthy controls (HCs) by enzyme-linked immunosorbent assay. Further, clinical parameters were measured properly. RESULTS: Serum irisin levels were significantly elevated in MG patients compared with HCs (p < 0.001). Furthermore, serum irisin levels were associated with the myasthenia gravis activities of daily living score in ocular myasthenia gravis (OMG) patients (r = 0.476, p = 0.004), but there was no relationship to be considered of any relevant value in generalized myasthenia gravis (GMG) patients. Acetylcholine receptor antibody-positive MG patients had higher serum irisin levels compared with HCs. Thymoma, endotracheal intubation, or intensive care unit treatments subsequently were not found to have effect on serum levels of irisin, but tendencies of increase were observed in negative ones. CONCLUSIONS: Serum irisin levels were elevated in patients with MG, suggesting its possible involvement in MG. And irisin is expected to be a signal to evaluate the activities of daily living of OMG patients, while its effect needs further study.

Roles of IL-35-producing T and B cells in anti-acetylcholine receptor antibody-positive myasthenia gravis.

BACKGROUND: Interleukin 35 (IL-35) plays an anti-inflammatory in numerous autoimmune diseases. However, the potential roles of IL-35-producing T and B cells and serum IL-35 levels in the pathogenesis of myasthenia gravis (MG) and its association with disease activity in patients with MG remain unclear. METHODS: The percentages of IL-35-producing CD4 + CD25 + T cells and CD19 + B cells among peripheral blood mononuclear cells were determined in 37 patients with anti-acetylcholine receptor (AChR) antibody-positive MG and 35 healthy controls (HCs) by performing a flow cytometry analysis. Serum IL-35 levels in participants were determined using an enzyme-linked immunosorbent assay. Further, the correlations between IL35 levels and disease activity were analysed. RESULTS: The percentages of IL-35-producing CD4 + CD25 + T cells and CD19 + B cells were significantly lower in patients with anti-AChR antibody-positive MG than in HCs (p = 0.001 and p = 0.002, respectively). Furthermore, patients with thymoma and patients with generalized MG had lower percentages of IL-35-producing CD4 + CD25 + T cells and CD19 + B cells than those without thymoma and those with ocular MG (p = 0.001 and p = 0.003; p = 0.008 and p = 0.001, respectively). Interestingly, the suppression of IL-35 secretion correlated negatively with the activities of daily living scores of patients with MG (r = -0.4774, p = 0.0028) and the quantitative MG scores (r = -0.4656, p = 0.0037). The proportions of IL-35-producing T cells and B cells and serum levels of IL-35 increased after treatment. CONCLUSIONS: IL-35 may represent a potential biomarker for the clinical evaluation of MG.

Knockdown of Microtubule Associated Serine/threonine Kinase Like Expression Inhibits Gastric Cancer Cell Growth and Induces Apoptosis by Activation of ERK1/2 and Inactivation of NF-κB Signaling.

Microtubule-associated serine/threonine kinase (MASTL) functions to regulate chromosome condensation and mitotic progression. Therefore, aberrant MASTL expression is commonly implicated in various human cancers. This study analyzed MASTL expression in gastric cancer vs. adjacent normal tissue for elucidating the association with clinicopathological data from patients. This work was then extended to investigate the effects of MASTL knockdown on tumor cells in vitro. The level of MASTL expression in gastric cancer tissue was assessed from the UALCAN, GEPIA, and Oncomine online databases. Lentivirus carrying MASTL or negative control shRNA was infected into gastric cancer cells. RT-qPCR, Western blotting, cell viability, cell counting, flow cytometric apoptosis and cell cycle, and colony formation assays were performed. MASTL was upregulated in gastric cancer tissue compared to the adjacent normal tissue, and the MASTL expression was associated with advanced tumor stage, Helicobacter pylori infection and histological subtypes. On the other hand, knockdown of MASTL expression significantly reduced tumor cell viability and proliferation, and arrested cell cycle at G2/M stage but promoted tumor cells to undergo apoptosis. At protein level, knockdown of MASTL expression enhanced levels of cleaved PARP1, cleaved caspase-3, Bax and p-ERK1/2 expression, but downregulated expression levels of BCL-2 and p-NF-κB-p65 protein in AGS and MGC-803 cells. MASTL overexpression in gastric cancer tissue may be associated with gastric cancer development and progression, whereas knockdown of MASTL expression reduces tumor cell proliferation and induces apoptosis. Further study will evaluate MASTL as a potential target of gastric cancer therapeutic strategy.

Increased serum IL-27 concentrations and IL-27-producing cells in MG patients with positive AChR-Ab.

OBJECTIVE: This study aims to explore the serum levels of IL-27 and the percentages of IL-27-producing cells in MG patients with positive acetylcholine receptor antibody (AChR-MG). METHODS: A total of 17 AChR-MG patients and 22 sex- and age- matched healthy controls (HCs) were recruited. Serum IL-27 levels were determined by enzyme linked immunosorbent assay. The percentages of IL-27+ cells, IL-27-producing T (CD3+IL-27+) cells, and IL-27-producing B (CD19+IL-27+) cells were measured by flow cytometry. RESULTS: Serum IL-27 levels in AChR-MG were significantly higher than those in HCs (13.44 ± 0.89 vs 7.14 ± 0.75 pg/mL, P < 0.0001), and were decreased after intravenous immunoglobulin (IVIG) treatment (P = 0.004). Moreover, the frequencies of IL-27+ lymphocytes were significantly elevated in AChR-MG patients than those in HCs (P = 0.011), and were decreased after IVIG treatment (P = 0.014). Furthermore, the frequencies of IL-27-producing T cells (P = 0.017) and IL-27-producing B cells (P = 0.015) were significantly elevated in AChR-MG patients as compared to those in HCs. Meanwhile, we observed positive correlations between the frequencies of IL-27+ lymphocytes and MG-ADL score (P = 0.030, r = 0.527). By contrast, no significant correlation was found between IL and 27 serum levels and MG-ADL score (P = 0.099, r = -0.414). CONCLUSION: IL-27 may play an important role in the pathological process in AChR-MG patients, and the frequencies of IL-27-producing (CD3+IL-27+) T cells may be a potential biomarker for predicting the severity of AChR-MG.

Interleukin-27 levels in patients with myasthenia gravis.

Interleukin-27 (IL-27), which belongs to IL-12 family, influences the function of T cells (Tregs) through regulating the expression, and function of forkhead box P3 (FoxP3). In this study, we detected the IL-27 serum levels in 59 myasthenia gravis (MG) patients and 35 healthy controls (HCs). Among them, 32 MG patients received immunoglobulin intravenous (IVIG) injections (0.4 g/kg per day for 5 consecutive days). IL-27 levels were collected before and after the treatments and subjected to a comparative study. Finally, we assessed the correlations of IL-27 levels with the clinical characteristics of MG. As a result, serum IL-27 levels were significantly higher in MG patients than those in the HCs. Meanwhile, significant reduction was detected after the IVIG treatment. IL-27 levels positively correlated with both MG activities of daily living and quantitative MG score. IL-27 may participate in the pathogenesis of MG and can be used as an early marker for the diagnosis and prognosis of MG. In addition, IL-27 can be used as a target for MG treatment through the regulation of specific immune signaling and maintaining immune homeostasis.

Increased serum IL-36γ levels are associated with disease severity in myasthenia gravis patients.

BACKGROUND: Interleukin 36 (IL-36), as a gradually recognized cytokine, is involved in the occurrence and evolution of autoimmune diseases. Nevertheless, the relationship between myasthenia gravis (MG) and IL-36 is rarely reported. METHODS: We evaluated the serum levels of IL-36 (IL-36α, IL-36ß and IL-36γ) by enzyme-linked immunosorbent assay (ELISA). Further, clinical parameters in 97 MG patients and 49 healthy controls (HCs) were carefully measured. RESULTS: Serum IL-36γ levels were significantly elevated in the MG patients compared with the HCs (p < 0.0001). Compared to those in remission, patients in the acute phase exhibited higher levels of IL-36α and IL-36γ (p = 0.038 and p = 0.011, respectively). Furthermore, patients with generalized MG (GMG) exhibited markedly higher serum IL-36γ levels than those with ocular MG (OMG) (p = 0.003). CONCLUSIONS: The serum levels of IL-36γ in patients with MG were increased and positively correlated with disease severity and may thus have potential as a serological MG marker.

Different clinical characteristics of longitudinally extensive transverse myelitis with and without connective tissue disorders: a single-center retrospective study.

BACKGROUND AND OBJECTIVE: Autoimmune longitudinal extensive transverse myelitis (LETM) is often combined with connective tissue disorders (CTD). The purpose of this study was to compare the clinical characteristics of autoimmune LETM with and without CTD. METHODS: Ninety-two patients diagnosed with autoimmune LETM were enrolled from our clinical database and divided into two groups depending on whether they had a concomitant diagnosis of CTD. Differences in clinical, serological, and imaging characteristics between the two groups were evaluated and compared. RESULTS: Fifty-nine LETM patients without CTD and 33 LETM patients with CTD were included. LETM patients with CTD had higher Kurtzke Expanded Disability Status Scale at nadir and more severe sensory dysfunction (p < 0.05) than those without CTD. It was also found that LETM patients with CTD, compared with those without CTD, had elevated levels of immune inflammation markers such as IgG, IgA, and globulins (p < 0.05). These abovementioned characteristics were more prominent in patients with aquaporin-4 antibodies (AQP4-ab) than in those without them. In addition, the most common type of CTD in LETM was Sjögren syndrome (SS), which was usually diagnosed at the time of LETM or later. CONCLUSION: LETM patients with CTD, especially those with AQP4-ab, had greater sensory dysfunction and higher levels of inflammatory markers than did LETM patients without CTD. Multicenter cooperation and long-term follow-up are necessary to further study the inherent implications and prognosis of the disease.

The analgesic efficacy and safety of peri-articular injection versus intra-articular injection in one-stage bilateral total knee arthroplasty: a randomized controlled trial.

BACKGROUND: As an essential component of multimodal analgesia approaches after total knee arthroplasty (TKA), local infiltration analgesia (LIA) can be classified into peri-articular injection (PAI) and intra-articular injection (IAI) according to administration techniques. Currently, there is no definite answer to the optimal choice between the two techniques. Our study aims to investigate analgesic efficacy and safety of PAI versus IAI in patients receiving simultaneous bilateral TKA. METHODS: This randomized controlled trial was conducted from February 2017 and finished in July 2018. Sixty patients eligible for simultaneous bilateral total knee arthroplasty were randomly assigned to receive PAI on one side and IAI on another. Primary outcomes included numerical rating scale (NRS) pain score at rest or during activity at 3 h, 6 h, 12 h, 24 h, 48 h, and 72 h following surgery. Secondary outcomes contained active or passive range of motion (ROM) at 1, 2, and 3 days after surgery, time to perform straight leg raise, wound drainage, operation time, and wound complications. RESULTS: Patients experienced lower NRS pain scores of the knee receiving PAI compared with that with PAI during the first 48 h after surgery. The largest difference of NRS pain score at rest occurred at 48 h (PAI: 0.68, 95%CI[0.37, 0.98]; IAI: 2.63, 95%CI [2.16, 3.09]; P < 0.001); and the largest difference of NRS pain score during activity also took place at 48 h (PAI: 2.46, 95%CI [2.07, 2.85]; IAI: 3.90, 95%CI [3.27, 4.52]; P = 0.001). PAI group had better results of range of motion and time to perform straight leg raise when compared with IAI group. There were no differences in operation time, wound drainage, and wound complication. CONCLUSION: PAI had the superior performance of pain relief and improvement of range of motion to IAI. Therefore, the administration technique of peri-articular injection is recommended when performing local infiltration analgesia after total knee arthroplasty. TRIAL REGISTRATION: The trial was retrospectively registered in the Chinese Clinical Trial Registry as ChiCTR1800020420 on 29th December, 2018. LEVEL OF EVIDENCE: Therapeutic Level I.

Elevated resistin levels may regulate high mobility group box 1 expression in Guillain-Barré syndrome.

Interactions among cytokines have important roles in the inflammatory processes underlying Guillain-Barré syndrome (GBS). Resistin and high mobility group box 1 (HMGB1) are involved in many inflammatory processes. This study examined 51 GBS patients, and found that serum resistin levels were elevated in 51 patients with GBS and correlated with HMGB1 levels. In vitro, resistin induced the release of HMGB1, interleukin (IL)-1ß, and IL-6 in THP-1 macrophages. This process was dependent on activation of p38 mitogen-activated protein kinase and NF-κB signaling pathways. These results suggest that signaling between resistin and HMGB1 might be a potential therapeutic target in GBS.

Decreased Sp1 Expression Mediates Downregulation of SHIP2 in Gastric Cancer Cells.

Past studies have shown that the Src homology 2-containing inositol 5-phosphatase 2 (SHIP2) is commonly downregulated in gastric cancer, which contributes to elevated activation of PI3K/Akt signaling, proliferation and tumorigenesis of gastric cancer cells. However, the mechanisms underlying the reduced expression of SHIP2 in gastric cancer remain unclear. While gene copy number variation analysis and exon sequencing indicated the absence of genomic alterations of SHIP2, bisulfite genomic sequencing (BGS) showed promoter hypomethylation of SHIP2 in gastric cancer cells. Analysis of transcriptional activity of SHIP2 promoter revealed Specificity protein 1 (Sp1) was responsible for the regulation of SHIP2 expression in gastric cancer cells. Furthermore, Sp1 expression, but not Sp3, was frequently downregulated in gastric cancer compared with normal gastric mucosa, which was associated with a paralleled reduction in SHIP2 levels in gastric cancer. Moreover, overexpression of Sp1 inhibited cell proliferation, induced apoptosis, suppressed cell motility and invasion in gastric cancer cells in vitro, which was, at least in part, due to transcriptional activation of SHIP2 mediated by Sp1, thereby inactivating Akt. Collectively, these results indicate that decreased expression of transcription factor Sp1 contributes to suppression of SHIP2 in gastric cancer cells.

Increased resistin levels in the serum and cerebrospinal fluid of patients with neuromyelitis optica.

INTRODUCTION: Resistin, which acts as a pro-inflammatory cytokine, has been implicated in the pathogenesis of several autoimmune diseases. However, the involvement of resistin in neuromyelitis optica (NMO), a severe inflammatory central nervous system disorder that targets the optic nerve and spinal cord, remains unclear. METHODS: We measured serum and cerebrospinal fluid (CSF) resistin levels in patients with NMO and controls matched by age and sex. The link between resistin levels and clinical variables in NMO was subsequently assessed. RESULTS: The concentrations of serum and CSF resistin were significantly higher in patients with NMO than in controls, and decreased following treatment with methylprednisolone. High sensitivity C-reactive protein (hs-CRP) levels and annualized relapse rate positively correlated with resistin levels in patients with NMO. CONCLUSION: Resistin might be a useful biomarker of inflammation in NMO, and a potential target for the treatment of NMO.

Suppression of SHIP2 contributes to tumorigenesis and proliferation of gastric cancer cells via activation of Akt.

BACKGROUND: The Src homology 2-containing inositol 5-phosphatase 2 (SHIP2) is implicated in diabetes, arthrosclerosis, and cancer. However, the role of SHIP2 in human gastric cancer remains unclear. METHODS: The expression levels of SHIP2 in gastric cancer tissues, a panel of gastric cancer cell lines, and normal gastric epithelial cells were analyzed by immunohistochemistry (IHC), Western blot, and real-time quantitative RT-PCR (qRT-PCR). Gastric cancer cells with either overexpressed SHIP2 or co-overexpressed SHIP2 and Akt were analyzed to determine cell proliferation, colony formation, apoptosis, cell migration, and invasion assays. Normal gastric epithelial cells with knockdown SHIP2 or co-knockdown SHIP2 and Akt were subjected by anchorage-independent growth assays. The effect of SHIP2 on tumor growth in vivo was detected by xenograft tumorigenesis assays. RESULTS: SHIP2 was commonly downregulated in gastric cancer compared with normal gastric mucosa, and overexpression of SHIP2 inhibited cell proliferation, induced apoptosis, suppressed cell motility and invasion in gastric cancer cells in vitro, and retarded the growth of xenograft gastric tumors in vivo, while knockdown of SHIP2 in normal gastric epithelial cells promoted anchorage-independent growth. Moreover, overexpression of SHIP2 inactivated Akt, and upregulated p21, p27, and the pro-apoptotic protein Bim. Restoring Akt activation in gastric cancer cells largely blocked the inhibition of PI3K/Akt signaling by SHIP2 and reversed the inhibitory effect of SHIP2 on tumorigenesis and proliferation. CONCLUSIONS: This study demonstrates, for the first time, that SHIP2 is frequently downregulated in gastric cancer, and reduced SHIP2 expression promotes tumorigenesis and proliferation of gastric cancer via activation of the PI3K/Akt signaling.

[Seroprevalance of Toxoplasma gondii infection and genotyping of the isolates from cancer patients in Anhui, eastern China].

OBJECTIVE: To investigate the seroprevalence of Toxoplasma gondii infection and identify the genotypes of T. gondii isolates from cancer patients in Anhui Province. METHODS: Three hundred and fifty-six blood samples were collected from outpatients and hospitalized cancer patients in Hefei, Anhui Province. IgG and gM antibodies specific to T gondii were determined by ELISA. The ELISA positive samples were subjected to detection of Toxoplasma DNA with PCR targeting a 529-bp repeat element of T. gondii. Genotyping of T. gondii isolates was performed using multilocus PCR-RFLP and 10 genetic markers, including 9 nuclear loci, sagl, sag2, sag3, btub, gra6, L358, pkl, c22-8, c29-2, and apico. RESULTS: Among 356 cancer patients, 21 (5.9%) cases were found to be IgG-positive and 8 (2.3%) were IgM-positive, and five of them were found to have both IgG and IgM antibodies. The total seroprevalence of Toxoplasma infection was 6.8%. Six PCR-positive samples were genotyped at 10 loci and two of them obtained all genetic markers and identified as the genotype of Chinese 1 (ToxoDB#9). CONCLUSION: In this study, latent and active toxoplasmosis exist in the patients with malignant tumors, and two isolates are genotyped as the type of Chinese 1 (ToxoDB#9) in Anhui, China.

Loss of PI(4,5)P2 5-Phosphatase A Contributes to Resistance of Human Melanoma Cells to RAF/MEK Inhibitors.

Past studies have shown that the inositol polyphosphate 5-phosphatase, phosphatidylinositol 4,5-bisphosphate 5-phosphatase (PIB5PA), is commonly downregulated or lost in melanomas, which contributes to elevated activation of phosphatidylinositol 3-kinase (PI3K)/Akt in melanoma cells. In this report, we provide evidence that PIB5PA deficiency plays a role in resistance of melanoma cells to RAF/mitogen-activated protein kinase kinase (MEK) inhibitors. Ectopic expression of PIB5PA enhanced apoptosis induced by the RAF inhibitor PLX4720 in BRAF(V600E) and by the MEK inhibitor U0126 in both BRAF(V600E) and wild-type BRAF melanoma cells. This was due to inhibition of PI3K/Akt, as co-introduction of an active form of Akt (myr-Akt) abolished the effect of overexpression of PIB5PA on apoptosis induced by PLX4720 or U0126. While overexpression of PIB5PA triggered activation of Bad and down-regulation of Mcl-1, knockdown of Bad or overexpression of Mcl-1 recapitulated, at least in part, the effect of myr-Akt, suggesting that regulation of Bad and Mcl-1 is involved in PIB5PA-mediated sensitization of melanoma cells to the inhibitors. The role of PIB5PA deficiency in BRAF inhibitor resistance was confirmed by knockdown of PIB5PA, which led to increased growth of BRAF(V600E) melanoma cells selected for resistance to PLX4720. Consistent with its role in vitro, overexpression of PIB5PA and the MEK inhibitor selumetinib cooperatively inhibited melanoma tumor growth in a xenograft model. Taken together, these results identify loss of PIB5PA as a novel resistance mechanism of melanoma to RAF/MEK inhibitors and suggest that restoration of PIB5PA may be a useful strategy to improve the therapeutic efficacy of the inhibitors in the treatment of melanoma.

PI(4,5)P2 5-phosphatase A regulates PI3K/Akt signalling and has a tumour suppressive role in human melanoma.

Inositol polyphosphate 5-phosphatases can terminate downstream signalling of phosphatidylinositol-3 kinase; however, their biological role in the pathogenesis of cancer is controversial. Here we report that the inositol polyphosphate 5-phosphatase, phosphatidylinositol 4,5-bisphosphate 5-phosphatase, has a tumour suppressive role in melanoma. Although it is commonly downregulated in melanoma, overexpression of phosphatidylinositol 4,5-bisphosphate 5-phosphatase blocks Akt activation, inhibits proliferation and undermines survival of melanoma cells in vitro, and retards melanoma growth in a xenograft model. In contrast, knockdown of phosphatidylinositol 4,5-bisphosphate 5-phosphatase results in increased proliferation and anchorage-independent growth of melanocytes. Although DNA copy number loss is responsible for downregulation of phosphatidylinositol 4,5-bisphosphate 5-phosphatase in a proportion of melanomas, histone hypoacetylation mediated by histone deacetylases HDAC2 and HDAC3 through binding to the transcription factor Sp1 at the PIB5PA gene promoter appears to be another commonly involved mechanism. Collectively, these results establish the tumour suppressive role of phosphatidylinositol 4,5-bisphosphate 5-phosphatase and reveal mechanisms involved in its downregulation in melanoma.

[Role of dysregulation of Bim in resistance of melanoma cells to endoplasmic reticulum stress-induced apoptosis].

OBJECTIVE: To establish a model of ER stress-induced apoptosis with tunicamycin and to examine whether Bim is dysregulated and its potential role in resistance of melanoma cells to apoptosis under endoplasmic reticulum (ER) stress. METHODS: A model of ER stress-induced apoptosis was established with tunicamycin. Apoptotic cells were quantitated using the annexin V/propidium iodide method by flow cytometry. Hoechst staining was also used to confirm the apoptotic cell death. Western blotting was used to measure the activation of caspase-3 and -9, and the expression of Bim, GRP78, CHOP, and Foxo1 at the protein level. The expression of Bim, CHOP and Foxo1 at the mRNA level was quantitated by qPCR. The siRNA technique was used to inhibit the expression of Bim. RESULTS: Treatment of the melanoma cells with tunicamycin did not induce significant apoptosis and activation of caspase cascade, whereas it caused marked activation of caspase-3 and -9, and apoptosis in HEK293 cells which were used as a control. With exposure to tunicamycin (3 µmol/L) for 12, 24, 36 hours the Bim protein levels were not increased in Mel-RM and MM200 cells. Its mRNA levels were 0.37 ± 0.05, 0.13 ± 0.02 and 0.02 ± 0.01 in Mel-RM cells, while 0.41 ± 0.06, 0.16 ± 0.04 and 0.21 ± 0.03 in MM200 cells, respectively. The expression of Bim mRNA was significantly reduced compared with that in the control groups of the two cell lines (P < 0.01). siRNA knockdown of Bim protected HEK293 cells against activation of caspase-3. The cell apoptosis of Bim siRNA group was (5.69 ± 0.38)%, significantly lower than that of the siRNA control group (40.32 ± 1.64)% and blank control group (35.46 ± 2.01)% (P < 0.01). In the melanoma cells after exposure to tunicamycin (3 µmol/L) for 6, 12, 24, and 36 hours the transcription factor CHOP at mRNA level were significantly increased and the expressions at protein level were also up-regulated. The expressions of another transcription factor Foxo1 at mRNA level significantly decreased and the expressions at protein level were down-regulated, too. CONCLUSIONS: The lack of Bim up-regulation contributes to the resistance of melanoma cells to ER stress-induced apoptosis and may be a mechanism by which melanoma cells adapt to ER stress conditions. Transcription factors CHOP and Foxo1 may be responsible for the dysregulation of Bim in melanoma cells upon ER stress.

MicroRNA-149*, a p53-responsive microRNA, functions as an oncogenic regulator in human melanoma.

The tumor suppressor p53 is activated in response to cellular stress to prevent malignant transformation by activation of the DNA repair machinery to preserve the cell, or by induction of apoptosis to eliminate the cell should the damage prove irrevocable. The gene encoding p53 frequently undergoes inactivating mutations in many human cancers, but WT p53 is often expressed at high levels in melanoma, which, as judged from the malignant nature of the disease, fails to act as an effective tumor suppressor. Here we show that p53 directly up-regulates microRNA-149* (miR-149*) that in turn targets glycogen synthase kinase-3α, resulting in increased expression of Mcl-1 and resistance to apoptosis in melanoma cells. Although deficiency in miR-149* undermined survival of melanoma cells and inhibited melanoma growth in a mouse xenograft model, elevated expression of miR-149* was found in fresh human metastatic melanoma isolates, which was associated with decreased glycogen synthase kinase-3α and increased Mcl-1. These results reveal a p53-dependent, miR-149*-mediated pathway that contributes to survival of melanoma cells, provides a rational explanation for the ineffectiveness of p53 to suppress melanoma, and identifies the expression of miR-149* as a mechanism involved in the increased expression of Mcl-1 in melanoma cells.