大肠癌组织脂联素和核转录因子-κB p65的表达及其意义

目的:研究脂联素和核转录因子-κBp65(NF-κBp65)在正常大肠组织和大肠癌组织中的表达变化,及其与临床病理指标的关系,以探讨其在大肠癌发生、发展和转移中的作用。方法:应用免疫组织化学SABC法,检测42例大肠癌组织、20例大肠腺瘤和42例大肠正常黏膜对照组织中脂联素与NF-κBp65的表达情况,以图像分析软件进行半定量测定。结果:脂联素在大肠癌组的表达明显低于大肠腺瘤和大肠正常黏膜〔(15.35±3.81)vs(38.71±6.80)vs(43.03±4.89),P<0.05〕,并随大肠癌的分化程度降低、淋巴结的转移、TNM分期的进展而下降;大肠癌组织中NF-κBp65表达水平明显高于大肠腺瘤和大肠正常黏膜〔(15.70±2.36)vs(27.15±6.11)vs(34.43±2.36),P<0.05〕,其表达随大肠癌分化程度降低、淋巴结转移、TNM分期的进展而增高;大肠癌组织脂联素表达强度与NF-κBp65表达强度之间呈明显负相关,r=-0.881,P<0.01。结论:大肠癌组织中脂联素低表达,NF-κBp65高表达,脂联素可能在大肠癌的发生发展中起重要作用,这种作用可能是通过抑制NF-κBp65途...     

Leptomycin B enhances CDDP-sensitivity via nuclear accumulation of p53 protein in HPV-positive cells

Cervical cancer, which commonly contains a wild-type p53 gene, is highly correlated with human papilloma virus (HPV) infection. Because the oncoprotein E6, derived from HPV, inhibits the function of p53 protein, the inhibition of apoptosis via the p53 pathway by HPV may be related to cisplatin (CDDP)-sensitivity in cervical cancer. We conducted the present study to determine whether and how HPV is related to CDDP-sensitivity in HPV-positive cervical cancer cells. We used cervical carcinoma cell lines HeLa with integrated HPV 18 and SiHa with integrated HPV 16. An HPV-negative cell line, Yumoto, with wild-type p53 gene was used as a control. Leptomycin B (LMB) enhanced sensitivity to CDDP and CDDP-induced apoptosis in HeLa and SiHa cells, but not in Yumoto cells. After exposure to LMB or CDDP alone, we observed weak p53 staining in HeLa, SiHa and Yumoto cells. Nuclear p53 staining was significantly increased by combined treatment with CDDP and LMB in HeLa and SiHa cells, but not in Yumoto cells. The expression of p53 and Bax protein increased with exposure to CDDP and was enhanced by LMB in HeLa and SiHa cells. The present study demonstrated that LMB enhanced CDDP-sensitivity via nuclear accumulation of p53 protein in HPV-positive cells.     

Bombesin stimulates nuclear factor kappa B activation and expression of proangiogenic factors in prostate cancer cells

The majority of deaths from prostate cancer occur in patients with androgen-insensitive metastatic disease. An important early event in the development of the metastatic phenotype is the induction of genes that promote angiogenesis, such as vascular endothelial growth factor (VEGF) and interleukin-8 (IL-8), which are released from tumor cells into their microenvironment. Coincident with progression from prostatic carcinoma in situ to metastatic disease is an increase in the number of tumor cells exhibiting neuroendocrine (NE) differentiation. NE cells express a variety of peptide hormones, including the bombesin (BBS)-like peptide, gastrin-releasing peptide (GRP), and its cognate receptor, GRP-R. Although there is a strong positive correlation between the degree of NE differentiation and the metastatic potential of prostate cancers, a mechanistic link between increased expression of peptide hormone receptors, such as GRP-R, and proangiogenic gene expression has not been established. Here we report that BBS stimulates nuclear factor kappa B (NF kappa B) activation and proangiogenic gene expression in the androgen-insensitive prostate cancer cells lines, PC-3 and DU-145. In PC-3 cells, BBS stimulation of GRP-R resulted in the up-regulation of IL-8 and VEGF expression through a NF kappa B-dependent pathway. We show that BBS treatment induced inhibitor of NF kappa B degradation, NF kappa B translocation to the cell nucleus, increased NF kappa B binding to its DNA consensus sequence, and increased IL-8 and VEGF mRNA expression and protein secretion. Treatment with the proteasome inhibitor, MG-132, blocked BBS-stimulated NF kappa B DNA binding, and IL-8 and VEGF expression and secretion. Finally, media collected from PC-3 cell cultures, after BBS treatment, stimulated an NF kappa B-dependent migration of human umbilical vascular endothelial cells in vitro. Together, our data demonstrate a role for BBS and GRP-R in the NF kappa B-dependent up-regulation of proangiogenic gene expression, and suggest a possible molecular mechanism linking NE differentiation and the increased metastatic potential of androgen-insensitive prostate cancers.     

Retracted: Genistein enhances the effect of epidermal growth factor receptor tyrosine kinase inhibitors and inhibits nuclear factor kappa B in nonsmall cell lung cancer cell lines

BACKGROUND:

Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR‐TKIs) have shown modest clinical benefit in patients with relapsed nonsmall cell lung cancer (NSCLC). Down‐regulation of Akt appears to correlate with the antitumor activity of EGFR‐TKIs. Akt activates nuclear factor kappa B (NF‐κB), which transcribes genes important for cell survival, invasion, and metastasis. The authors hypothesized that genistein, through the inhibition of NF‐κB, could enhance the activity of EGFR‐TKIs in NSCLCs.

METHODS:

Three NSCLC cell lines with various EGFR mutation status and sensitivities to EGFR‐TKIs were selected: H3255 (L858R), H1650 (del E746‐A750), and H1781 (wild‐type EGFR). Cells were treated with erlotinib, gefitinib, genistein, or the combination of each of the EGFR‐TKIs with genistein. Cell survival and apoptosis were assessed, and expression levels of EGFR, pAkt, cyclooxygenase‐2 (COX‐2), E‐cadherin, prostaglandin E₂ (PGE₂), and NF‐κB were measured.

RESULTS:

Both EGFR‐TKIs demonstrated growth inhibition and apoptosis in each of the cell lines, but H1650 and H1781 were much less sensitive. Genistein demonstrated some antitumor activity in all cell lines, but enhanced growth inhibition and apoptosis when combined with the EGFR‐TKIs in each of the cell lines. Both combinations down‐regulated NF‐κB significantly more than either agent alone in H3255. In addition, the combinations reduced the expression of EGFR, pAkt, COX‐2, and PGE_2, consistent with inactivation of NF‐κB.

CONCLUSIONS:

The authors concluded that genistein enhances the antitumor effects of EGFR‐TKIs in 3 separate NSCLC cell lines. This enhanced activity is in part because of greater reduction in the DNA‐binding activity of NF‐κB when EGFR‐TKIs were combined with genistein. Cancer 2009. © 2009 American Cancer Society.     

Contributions of mitogen-activated protein kinase and nuclear factor kappa B to N-(4-hydroxyphenyl)retinamide-induced apoptosis in prostate cancer cells

The synthetic retinoid N-(4-hydroxyphenyl)retinamide (4-HPR) has been shown to induce apoptosis in various types of tumors, including prostate cancer. We sought to examine the key mechanisms affecting the resistance to 4-HPR-induced apoptosis in three human prostate cancer cell lines, PC-3, DU145, and LNCaP. Concentrations of more than 40 microM 4-HPR produced apoptosis to almost the same extent in all cell lines; however, only the LNCaP line remained highly sensitive to concentrations less than 10 microM. These differing sensitivities at low concentrations correlated well with the level of constitutive activation of nuclear factor kappa B (NFkappaB) in the individual cell lines. We found that NFkappaB activation inhibited c-jun NH(2)-terminal kinase and caspase 3 activation induced by 4-HPR and that NFkappaB inhibition by the I kappa B alpha phosphorylation inhibitor compound Bay 117082 resulted in increasing sensitization of both PC-3 and DU145 lines to apoptosis induced by 4-HPR at low concentrations. Furthermore, we found that inhibition of extracellular signal-regulated kinase (ERK) enhanced the suppression of NFkappaB by 4-HPR and also resulted in sensitization to apoptosis in the DU145 cell line, in which ERK is activated constitutively. It thus appears that mitogen-activated protein kinase associated with the activity of NFkappaB plays an important role in the degree of resistance to 4-HPR-induced apoptosis in human prostate cancer cells.     

Downregulation of survivin is associated with reductions in TNF receptors' mRNA and protein and alterations in nuclear factor kappa B signaling in urothelial cancer cells

Because survivin is selectively expressed in and associated with an unfavorable prognosis in transitional cell carcinoma of the bladder (TCC), we treated T-24 cells with survivin siRNA. Survivin siRNA treatment caused a profound decrease of survivin protein that was associated with decreased cell growth, a specific G2/M arrest and increased cytochrome c release. Microarray analysis of apoptosis genes showed that levels of 14/114 gene products were decreased after 72 hours treatment with survivin siRNA, including survivin, three TNF receptors, Akt, c-Abl, caspases and their related genes and Bcl-2 and NF-κB signaling related genes. TNFR1, pro-caspase-2 and Akt protein levels were decreased after survivin siRNA treatment for 48 and 72 hours. Downregulation of survivin causes changes in mitosis and apoptosis, which may be related to changes in TNF receptors and NF-κB signaling.     

Synergistic tumor suppression by coexpression of FUS1 and p53 is associated with down-regulation of murine double minute-2 and activation of the apoptotic protease-activating factor 1-dependent apoptotic pathway in human non-small cell lung cancer cells

FUS1 is a novel tumor suppressor gene identified in human chromosome 3p21.3 region. Loss of expression and deficiency of posttranslational modification of FUS1 protein have been found in a majority of human lung cancers. Restoration of wild-type FUS1 in 3p21.3-deficient human lung cancer cells exhibited a potent tumor suppression function in vitro and in vivo. In this study, we evaluated the combined effects of FUS1 and tumor suppressor p53 on antitumor activity and explored the molecular mechanisms of their mutual actions in human non-small cell lung cancer (NSCLC) cells. We found that coexpression of FUS1 and p53 by N-[1-(2,3-dioleoyloxyl)propyl]-NNN-trimethylammoniummethyl sulfate:cholesterol nanoparticle-mediated gene transfer significantly and synergistically inhibited NSCLC cell growth and induced apoptosis in vitro. We also found that a systemic treatment with a combination of FUS1 and p53 nanoparticles synergistically suppressed the development and growth of tumors in a human H322 lung cancer orthotopic mouse model. Furthermore, we showed that the observed synergistic tumor suppression by FUS1 and p53 concurred with the FUS1-mediated down-regulation of murine double minute-2 (MDM2) expression, the accumulation and stabilization of p53 protein, as well as the activation of the apoptotic protease-activating factor 1 (Apaf-1)-dependent apoptotic pathway in human NSCLC cells. Our results therefore provide new insights into the molecular mechanism of FUS1-mediated tumor suppression activity and imply that a molecular therapy combining two or more functionally synergistic tumor suppressors may constitute a novel and effective strategy for cancer treatment.