Role of PGE2 Receptors in Mouse Skin Cancer

PGE2 受体在小鼠皮肤癌中的作用

• 批准号: 8336639
• 负责人: Robert Langenbach
• 金额: $ 55.4万
• 依托单位: NATIONAL INSTITUTE OF ENVIRONMENTAL HEALTH SCIENCES
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/8336639
• 关键词: Affect; Agonist; Agreement; Alcohols; Alprostadil; Apoptosis; CREB1 gene; Cell Surface Receptors; Cell Survival; Chemoprevention; Complex; Cyclic AMP; Cyclic AMP-Dependent Protein Kinases; Data; Development; Dinoprostone; Dose; Epidermal Growth Factor Receptor; Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor; Epidermis; Family; G-Protein-Coupled Receptors; GTP-Binding Proteins; Goals; Indomethacin; Investigation; MAPK3 gene; Malignant Neoplasms; Measures; Mediating; Modeling; Mus; PKA inhibitor; PTGS2 gene; Pathway interactions; Play; Production; Prostaglandin-Endoperoxide Synthase; Receptor Activation; Receptor Inhibition; Regulation; Reporting; Role; STAT3 gene; Signal Pathway; Signal Transduction; Skin; Skin Cancer; Skin Neoplasms; Therapeutic; Time; Topical application; Transducers; UVB induced; Ultraviolet B Radiation; Wild Type Mouse; arrestin B; butaprost; carcinogenesis; celecoxib; chemotherapy; cyclooxygenase 1; human WFDC2 protein; inhibitor/antagonist; keratinocyte; protective effect; receptor; response; survivin; transcription factor; tumor

We previously reported that the prostaglandin E2 (PGE2) G protein coupled receptor (GPCR), EP2, plays important roles in mouse skin tumor development using the initiation promotion model (Chun et al., Carcinogenesis, 30:1620, 2009). Because keratinocyte proliferation is essential for skin tumor development, EP2-mediated signaling pathways that could contribute to keratinocyte proliferation were investigated. A single topical application of the EP2 agonist, butaprost, dose-dependently increased keratinocyte replication and activated EGFR and PKA; and inhibition of either EGFR or PKA (AG1478 or H89, respectively) decreased butaprost-induced keratinocyte proliferation by 70%. Because previous studies indicated that GPCR activation of EGFR involved a b-arrestin1/Src complex, the possibility of EP2 acting via this mechanism in keratinocytes was investigated. It was observed that butaprost increased Src and EGFR activation and induced b-arrestin1/Src complex formation. b-arrestin1-deficiency reduced Src and EGFR activation, confirming b-arrestin1s role in their activation. In agreement with b-arrestin1 contributing to Src and EGFR activation, studies with Src and EGFR inhibitors (PP2 and AG1478, respectively) indicated Src to be upstream of EGFR. Butaprost also induced the activation of Akt, ERK1/2, and STAT3; and either b-arrestin1-deficiency or EGFR inhibition decreased their activation, confirming roles for b-arrestin1 and EGFR in their activation. In addition to EGFR activation, butaprost also increased cAMP levels and PKA activation, as measured by p-GSK3b and p-CREB formation. The PKA inhibitor, H89, decreased butaprost-induced GSK3b, CREB, and ERK activation, but did not affect EGFR activation. Thus, our recent results indicate that EP2 contributed to mouse keratinocyte proliferation by G protein independent, barrestin1 dependent activation of EGFR, and G protein dependent activation of PKA. In addition to EP2 contributing to skin tumor formation in the initiation/promotion model (Chun et al., Carcinogenesis, 30:1620, 2009), we previously reported that EP2 played a role in an anti-apoptotiic response in UVB-exposed mouse skin (Chun et al. Cancer Res., 67:2015, 2007). Because survivin is a regulator of cell survival, the possible regulation of survivin by COX-2 and EP2 in UVB-exposed mouse skin was investigated. In wild type mouse skin UVB time-dependently increased the levels of COX-2, survivin and phosphorylated-signal transducer and activator of transcription3 (p-STAT3), a transcription factor that regulates survivin expression; and COX-2- or EP2-deficiency significantly reduced their induction. Topical application of the COX-2 selective inhibitor, celecoxib, also reduced UVB-induced survivin levels. To further investigate the roles of PGE2 and EP2 in the regulation of survivin, indomethacin was used to inhibit UVB-induced endogenous PG production. Indomethacin reduced UVB-induced survivin levels, while PGE2 and the EP2 agonist, butaprost, partially restored survivin levels. The epidermal growth factor receptor (EGFR) is a downstream effector of EP2 and inhibition of EGFR (AG1478) significantly reduced UVB induction of survivin and activation of STAT3. UVB-induced epidermal apoptosis in COX-2-/- mice was reduced by butaprost and EGFR inhibition blocked butaprosts protective effects. Furthermore, butaprost in the absence of UVB exposure time-dependently increased p-EGFR, p-STAT3 and survivin levels in nave mouse skin, whereas the EP4 agonist, PGE1 alcohol, did not significantly increase p-STAT3 or survivin levels. These data suggest that COX-2-generated PGE2 regulates survivin expression in mouse skin via an EP2-mediated EGFR/STAT3 pathway, and inhibiting the EP2/survivin pathway may provide a therapeutic strategy for the chemoprevention/chemotherapy of UVB-induced skin cancer.

我们先前报道说，前列腺素E2（PGE2）G蛋白偶联受体（GPCR）EP2使用起始促进模型在小鼠皮肤肿瘤发育中起着重要作用（Chun等人，癌症，30：1620，2009）。由于角质形成细胞增殖对于皮肤肿瘤的发育至关重要，因此研究了EP2介导的信号传导途径可能有助于角质形成细胞增殖。 EP2激动剂，dubrost，剂量依赖性地增加角质形成细胞复制并激活EGFR和PKA的单个局部应用；抑制EGFR或PKA（分别为AG1478或H89），将丁二醇诱导的角质形成细胞增殖降低了70％。由于先前的研究表明，EGFR的GPCR激活涉及B-arrestin1/SRC复合物，因此研究了EP2通过这种机制在角质形成细胞中作用的可能性。据观察，ButAdost增加了SRC和EGFR激活，并诱导B-arrestin1/SRC复合物的形成。 b-arrestin1缺乏降低了SRC和EGFR激活，确认了B-arrestin1s在其激活中的作用。与有助于SRC和EGFR激活的B-arrestin1一致，SRC和EGFR抑制剂（分别为PP2和AG1478）的研究表明SRC是EGFR的上游。 Butaprost还诱导了Akt，ERK1/2和STAT3的激活。 B-arrestin1缺乏症或EGFR抑制作用降低了其激活，证实了B-arrestin1和EGFR在激活中的作用。除EGFR激活外，通过P-GSK3B和P-CREB的形成测量，Butaprost还增加了cAMP水平和PKA激活。 PKA抑制剂H89降低了Butaprost诱导的GSK3B，CREB和ERK激活，但不会影响EGFR激活。因此，我们最近的结果表明，EP2通过G蛋白独立，barrestin1的依赖性EGFR激活和G蛋白依赖PKA的激活促进了小鼠角质形成细胞的增殖。 除了在开始/促进模型中导致皮肤肿瘤形成的EP2（Chun等人，癌变，30：1620，2009）外，我们先前曾报道过EP2在UVB暴露的小鼠皮肤中在抗磷酸反应中发挥了作用（Chun等人Cancer。，67：2015：2015：2015：2015，2007年）。由于Survivin是细胞存活的调节剂，因此研究了COX-2和EP2在UVB暴露的小鼠皮肤中可能调节Survivin。在野生型小鼠皮肤中，UVB时间依赖性地增加了Cox-2的水平，Survivin和磷酸化 - 信号传感器和转录3（P-STAT3）的激活因子（P-STAT3），这是一种调节Survivin表达的转录因子；和COX-2-或EP2缺乏效率可显着降低其诱导。 COX-2选择性抑制剂Celecoxib的局部应用也降低了UVB诱导的遗传水平。为了进一步研究PGE2和EP2在Survivin调节中的作用，吲哚美辛用于抑制UVB诱导的内源性PG产生。吲哚美辛降低了UVB诱导的存活水平，而PGE2和EP2激动剂（丁加罗斯特）部分恢复了生存水平。表皮生长因子受体（EGFR）是EP2的下游效应子，EGFR（AG1478）的抑制显着降低了UVB诱导survivin和STAT3的激活。 ButAdrost和EGFR抑制作用降低了COX-2 - / - 小鼠中UVB诱导的表皮细胞凋亡。此外，在不存在UVB暴露时，dubrost在时间依赖性地依赖性地增加了小鼠皮肤中的P-EGFR，P-STAT3和Survivin水平，而EP4激动剂PGE1酒精并未显着提高P-STAT3或Survivin水平。这些数据表明，COX-2生成的PGE2通过EP2介导的EGFR/STAT3途径调节小鼠皮肤中的Survivin表达，并抑制EP2/Survivin途径可以为UVB诱导的皮肤癌的化学预防/化学疗法提供治疗策略。