Liang-Ming Lee

Quercetin induces mitochondrial-derived apoptosis via reactive oxygen species-mediated ERK activation in HL-60 leukemia cells and xenograft

Abstract Quercetin is a plant-derived bioflavonoid that was recently shown to have multiple anticancer activities in various solid tumors. Here, novel molecular mechanisms through which quercetin exerts its anticancer effects in acute myeloid leukemia (AML) cells were investigated. Results from Western blot and flow cytometric assays revealed that quercetin significantly induced caspase-8, caspase-9, and caspase-3 activation, poly ADP-ribose polymerase (PARP) cleavage, and mitochondrial membrane depolarization in HL-60 AML cells. The induction of PARP cleavage by quercetin was also observed in other AML cell lines: THP-1, MV4-11, and U937. Moreover, treatment of HL-60 cells with quercetin induced sustained activation of extracellular signal-regulated kinase (ERK), and inhibition of ERK by an ERK inhibitor significantly abolished quercetin-induced cell apoptosis. MitoSOX red and 2′,7′-dichlorofluorescin fluorescence, respectively, showed that mitochondrial superoxide and intracellular peroxide levels were higher in quercetin-treated HL-60 cells compared with the control group. Moreover, both N-acetylcysteine and the superoxide dismutase mimetic, MnTBAP, reversed quercetin-induced intracellular reactive oxygen species production, ERK activation, and subsequent cell death. The in vivo xenograft mice experiments revealed that quercetin significantly reduced tumor growth through inducing intratumoral oxidative stress while activating the ERK pathway and subsequent cell apoptosis in mice with HL-60 tumor xenografts. In conclusions, our results indicated that quercetin induced cell death of HL-60 cells in vitro and in vivo through induction of intracellular oxidative stress following activation of an ERK-mediated apoptosis pathway.

Pterostilbene simultaneously induced G0/G1-phase arrest and MAPK-mediated mitochondrial-derived apoptosis in human acute myeloid leukemia cell lines.

Background Pterostilbene (PTER) is a dimethylated analog of the phenolic phytoalexin, resveratrol, with higher anticancer activity in various tumors. Herein, the molecular mechanisms by which PTER exerts its anticancer effects against acute myeloid leukemia (AML) cells were investigated. Methodology and Principal Findings Results showed that PTER suppressed cell proliferation in various AML cell lines. PTER-induced G0/G1-phase arrest occurred when expressions of cyclin D3 and cyclin-dependent kinase (CDK)2/6 were inhibited. PTER-induced cell apoptosis occurred through activation of caspases-8-9/-3, and a mitochondrial membrane permeabilization (MMP)-dependent pathway. Moreover, treatment of HL-60 cells with PTER induced sustained activation of extracellular signal-regulated kinase (ERK)1/2 and c-Jun N-terminal kinase (JNK)1/2, and inhibition of both MAPKs by their specific inhibitors significantly abolished the PTER-induced activation of caspases-8/-9/-3. Of note, PTER-induced cell growth inhibition was only partially reversed by the caspase-3-specific inhibitor, Z-DEVE-FMK, suggesting that this compound may also act through a caspase-independent pathway. Interestingly, we also found that PTER promoted disruption of lysosomal membrane permeabilization (LMP) and release of activated cathepsin B. Conclusion Taken together, our results suggest that PTER induced HL-60 cell death via MAPKs-mediated mitochondria apoptosis pathway and loss of LMP might be another cause for cell apoptosis induced by PTER.

Combined Effects of ICAM-1 Single-Nucleotide Polymorphisms and Environmental Carcinogens on Oral Cancer Susceptibility and Clinicopathologic Development

Background In Taiwan, oral cancer has causally been associated with environmental carcinogens. Intercellular adhesion molecule (ICAM)-1, a cell adhesion molecule with a key role in inflammation and immunosurveillance, was implicated in carcinogenesis by facilitating instability in the tumor environment. The current study explored the combined effect of ICAM-1 gene polymorphisms and exposure to environmental carcinogens on the susceptibility of developing oral squamous cell carcinoma (OSCC) and the clinicopathological characteristics of the tumors. Methodology and Principal Findings Four single-nucleotide polymorphisms (SNPs) of the ICAM-1 gene from 595 patients with oral cancer and 561 non-cancer controls were analyzed by a real-time PCR. We found that the ICAM-1 rs5498 polymorphism and the TAGG or TACG haplotype of 4 ICAM-1 SNPs (rs3093030, rs5491, rs281432, and rs5498) combined were associated with oral-cancer susceptibility. Among 727 smokers, ICAM-1 polymorphisms carriers with the betel-nut chewing habit had a 27.49–36.23-fold greater risk of having oral cancer compared to ICAM-1 wild-type (WT) carriers without the betel-nut chewing habit. Among 549 betel-nut chewers, ICAM-1 polymorphisms carriers who smoked had a 9.93–14.27-fold greater risk of having oral cancer compared to those who carried the WT but did not smoke. Finally, patients with oral cancer who had at least 1 T allele of ICAM-1 rs5491 or 1 G allele of rs281432 were at lower risk of developing an advanced clinical stage (III/IV) (p<0.05), compared to those patients with AA or CC homozygotes. Conclusions Our results suggest that the ICAM-1 rs5498 SNP and either of 2 haplotypes of 4 SNPs combined have potential predictive significance in oral carcinogenesis. Gene-environment interactions of ICAM-1 polymorphisms, smoking, and betel-nut chewing might alter oral-cancer susceptibility. ICAM-1 rs5491 and rs281432 may be applied as factors to predict the clinical stage in OSCC patients.

Nobiletin suppresses the proliferation and induces apoptosis involving MAPKs and caspase-8/-9/-3 signals in human acute myeloid leukemia cells

Nobiletin, a compound isolated from citrus fruits, is a polymethoxylated flavone derivative that was shown to have anti-inflammatory and anticancer activities in various solid tumors. The anticancer effect of nobiletin on nonsolid tumor remains unclear. Herein, the molecular mechanisms by which nobiletin exerts its anticancer effects on acute myeloid leukemia (AML) cells were investigated. The results showed that nobiletin suppressed cell proliferation in various types of AML cell lines. Moreover, nobiletin induced cell-cycle arrest of HL-60 AML cells at the G0/G1 phase by suppressing extracellular signal-regulated kinase (ERK) activity. Furthermore, nobiletin effectively induced apoptosis of HL-60 cells through caspase-8, caspase-9, and caspases-3 activation concomitantly with a marked induction of p38 mitogen-activated protein kinase (MAPK) activation, but without affecting expression levels of Bcl-2, Bax, or Bid. Taken together, our results suggest that nobiletin inhibited HL-60 cell proliferation through inducing cell-cycle arrest and apoptosis and could serve as a potential additional chemotherapeutic agent for treating AML.

A Large Urinary Bladder Hemangioma Mimicking Urachal Cancer: A Case Report and Literature Review

Urinary bladder hemangiomas are rare, especially in children and adolescents. We present a case of a 17-year-old young man with persistent gross hematuria for 1 month. Computed tomography revealed a 3.6 cm mass on the superior anterior wall of the urinary bladder, which was highly suspected as an urachal tumor. We carried out an en bloc resection of the urachus and bladder tumor. The pathologic report indicated a cavernous hemangioma of the urinary bladder. No tumor recurrence or bleeding was found during the 2-year follow-up. Urinary bladder hemangioma is an important differential diagnosis in young patients with hematuria.

Do 5α-reductase inhibitors prevent secondary benign prostate hyperplasia-related urinary retention?

Objective: The objective of this study is to determine whether 5α-reductase inhibitors (5ARIs) prevent secondary benign prostate hyperplasia (BPH)-related acute urinary retention (AUR) after the first episode of urine retention. Materials and Methods: In total, 1161 patients were enrolled using the International Classification of Diseases, Ninth Revision (ICD-9) codes as having AUR (ICD-9 code 788.20) and BPH, with or without lower urinary tract symptoms (ICD-9 codes 600.0 and 600.1) between January 2006 and June 2016. After excluding patients with bladder and external sphincter dysfunction, we enrolled 128 patients in this study. Patients were divided into two groups: Group 1 comprising 33 patients receiving 5ARI (dutasteride) and α-blocker treatment, and Group 2 comprising 95 patients receiving α-blocker treatment alone. Patient characteristics, namely, age, prostate size, maximal urinary flow rate (Qmax), prostate-specific antigen (PSA) level, and duration of dutasteride treatment, were recorded and compared. Patients were followed for at least 6 months to a maximum period of 24 months if no event occurred. Events of secondary BPH-related AUR and surgery were recorded. Results: All patient characteristics, except for prostate size, were similar between the two groups (Group 1 vs. Group 2: 65.0 vs. 36.9 mL, P = 0.001). In total, 43 patients (32%) experienced secondary AUR within 24 months. The rate of secondary BPH-related AUR was significantly lower in the Group 1 than in the Group 2 (18.2% vs. 39.4%, P = 0.030). The rate of BPH-related surgery was lower in the Group 1 (9.1% vs. 14.9%, P = 0.410), although the difference was not significant. Prostate size and PSA levels were significantly lower in the Group 1 (23.5%) than in the Group 2 (60.4%) (P < 0.001). Conclusions: Using 5ARIs to treat patients with first episodes of BPH-related AUR significantly prevents secondary AUR.