Article

The Role of STAT-3 in the Induction of Apoptosis in Pancreatic Cancer Cells by Benzyl Isothiocyanate

Department of Pharmaceutical Sciences and Cancer Biology Center, School of Pharmacy, Texas Tech University Health Sciences Center, Amarillo, TX 79106, USA.
CancerSpectrum Knowledge Environment (Impact Factor: 15.16). 02/2009; 101(3):176-93. DOI: 10.1093/jnci/djn470
Source: PubMed

ABSTRACT Benzyl isothiocyanate (BITC), a compound found in cruciferous vegetables, has been reported to have anticancer properties, but the mechanism whereby it inhibits growth of human pancreatic cancer cells is incompletely understood.
Human pancreatic cancer cells (BxPC-3, AsPC-1, Capan-2, MiaPaCa-2, and Panc-1) and immortalized human pancreatic cells (HPDE-6) were treated with vehicle or with BITC at 5-40 microM, cell survival was evaluated by sulforhodamine B assay, and apoptosis by caspase-3 and poly-ADP ribose polymerase cleavage or by a commercial assay for cell death. Total and activated signal transducer and activator of transcription-3 (STAT-3) protein expression in the cells were examined by western blotting, STAT-3 mRNA levels by reverse transcription-polymerase chain reaction, and STAT-3 DNA-binding and transcriptional activity by commercially available binding and reporter assays. The effects of BITC treatment on tumor growth, apoptosis, and STAT-3 protein expression in vivo were studied in xenografts of BxPC-3 pancreatic tumor cells in athymic nude mice. All statistical tests were two-sided.
BITC treatment reduced cell survival and induced apoptosis in BxPC-3, AsPC-1, Capan-2, and MiaPaCa-2 cells, and to a much lesser extent in Panc-1 cells, but not in HPDE-6 cells. It also reduced levels of activated and total STAT-3 protein, and as a result, STAT-3 DNA-binding and transcriptional activities. Overexpression of STAT-3 in BxPC-3 cells inhibited BITC-induced apoptosis and restored STAT-3 activity. In mice that were fed BITC (60 micromol/wk, five mice, 10 tumors per group), growth of BxPC-3 pancreatic tumor xenografts was suppressed compared with control mice (at 6 weeks, mean tumor volume of control vs BITC-treated mice = 334 vs 172 mm3, difference =162 mm3, 95% confidence interval = 118 to 204 mm3; P = .008) and tumors had increased apoptosis and reduced STAT-3 protein expression.
BITC induces apoptosis in some types of pancreatic cancer cells by inhibiting the STAT-3 signaling pathway.

0 Followers
 · 
94 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Anoikis is an anchorage-independent cell death. Resistance to anoikis is one of the key features of metastatic cells. Here, we analyzed the role of STAT3 in anoikis resistance in melanoma cells leading to metastasis. When grown under anchorage-independent conditions, significant proportion of cells resisted anoikis and these resistant cells had higher rate of migration and invasion as compared to the cells grown under anchorage-dependent conditions. The anoikis resistant cells also had significantly higher expression and phosphorylation of STAT3 at Y705 than the cells that were attached to the basement membrane. STAT3 inhibitors, AG 490 and piplartine (PL) induced anoikis in a concentration-dependent manner in anoikis resistant cells. Over-expression of STAT3 or treatment with IL-6 not only increased anoikis resistance, but also protected the cancer cells from PL-induced anoikis. On the other hand, silencing STAT3 decreased the potential of cancer cells to resist anoikis and to migrate. STAT3 knock-down cells and PL treated cells did not form tumors as well as failed to metastasize in SCID-NSG mice as compared to untreated anchorage-independent cells, which formed big tumors and extensively metastasized. In summary, our results for the first time establish STAT3 as a critical player that renders anoikis resistance to melanoma cells and enhance their metastatic potential.
    Oncotarget 08/2014; 5(16):7051-7064.
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Previous studies regarding the association between cruciferous vegetable intake and pancreatic cancer risk have reported inconsistent results. We conducted a meta-analysis to demonstrate the potential association between them. A systematic literature search of papers was conducted in March 2014 using PubMed, EMBASE, and Web of Science, and the references of the retrieved articles were screened. The summary odds ratios (ORs) with 95% confidence interval (CI) for the highest versus the lowest intake of cruciferous vegetables were calculated. Four cohort and five case-control studies were eligible for inclusion. We found a significantly decreased risk of pancreatic cancer associated with the high intake of cruciferous vegetables (OR 0.78, 95% CI 0.64-0.91). Moderate heterogeneity was detected across studies (P = 0.065). There was no evidence of significant publication bias based on Begg's funnel plot (P = 0.917) or Egger's test (P = 0.669). Cruciferous vegetable intake might be inversely associated with pancreatic cancer risk. Because of the limited number of studies included in this meta-analysis, further well-designed prospective studies are warranted to confirm the inverse association between cruciferous vegetable intake and risk of pancreatic cancer.
    World Journal of Surgical Oncology 12/2015; 13(1):454. DOI:10.1186/s12957-015-0454-4
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Tumor cells need to attain anoikis resistance to survive prior to metastasis making it a vital trait of malignancy. The mechanism by which pancreatic cancer cells resist anoikis and metastasize is not well established. Significant proportion of pancreatic cancer cells resisted anoikis when grown under anchorage-independent conditions. The cells that resisted anoikis showed higher migratory and invasive characteristics than the cells that were cultured under anchorage dependent condition. Interestingly, anoikis resistant cells exhibited significantly increased expression and phosphorylation of STAT3 at Tyr 705, as compared to adherent cells. AG 490 and piplartine (PL) induced significant anoikis in anoikis resistant pancreatic cancer cells. Silencing STAT3 not only reduced the capacity of pancreatic cancer cells to resist anoikis but also reversed its invasive characteristics. IL-6 treatment and over-expression of STAT3 enhanced anoikis resistance and protected the cells from PL-induced anoikis. PL-treated cells completely failed to develop tumors when injected subcutaneously in immune-compromised mice. Moreover, these cells also failed to metastasize when injected intravenously. On the other hand, untreated anoikis resistant cells not only formed aggressive tumors but also metastasized substantially to lungs and liver when injected intravenously. Metastatic nodules formed by untreated anoikis resistant cells in lungs exhibited significant phosphorylation of STAT3 at Tyr705. Taken together, our results established the critical involvement of STAT3 in conferring anoikis resistance to pancreatic cancer cells and increased metastasis. © The Author 2014. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.
    Carcinogenesis 11/2014; 36(1). DOI:10.1093/carcin/bgu233

Full-text (2 Sources)

Download
39 Downloads
Available from
May 26, 2014