Balster Douglas A, O'Dorisio M Sue, Albers Anne R, Park Sang K, Qualman Stephen J
Department of Pathology, The Ohio State University, Columbus, OH 43205, USA.
Regul Pept. 2002 Nov 15;109(1-3):155-65. doi: 10.1016/s0167-0115(02)00199-4.
We hypothesize that vasoactive intestinal peptide (VIP) promotes neural crest differentiation through VIP receptor type I (VPAC1). In order to test this hypothesis, SKNSH neuroblastoma cells were stably transfected with VPAC1 and receptor expression was verified by real-time RT-PCR. Overexpression of VPAC1 in SKNSH cells resulted in upregulation of endogenous retinoic acid receptor expression for both RARalpha and RXRalpha with no change in expression of RARbeta. Transfected cells demonstrated high affinity binding of VIP (K(D)=0.2 nM) and VIP-mediated stimulation of adenylate cyclase and a shift in cell cycle kinetics to a near triploid DNA index in G1. SKNSH/VPAC1 cells treated with VIP were observed to express a more differentiated phenotype compared to wild type cells as characterized by an increase in tissue transglutaminase II and a decrease in bcl-2 immunostaining. VIP-induced differentiation effects were potentiated by retinoic acid. This differentiation resulted in decreased proliferative potential in a xenograft model. Whereas, wild type SKNSH cells induced tumor growth in 100% of nude mice within 13 days post-injection, SKNSH transfected with VPAC1 demonstrated no tumor formation in xenografts followed for 6 months. Taken together, these data support the hypothesis that VIP modulation of neural crest differentiation is mediated via VPAC1 and that high expression of VPAC1 induces differentiation in and decreases tumorigenicity of neuroblastoma cells.
我们推测血管活性肠肽（VIP）通过I型VIP受体（VPAC1）促进神经嵴分化。为了验证这一推测，我们用VPAC1稳定转染了SKNSH神经母细胞瘤细胞，并通过实时RT-PCR验证了受体表达。SKNSH细胞中VPAC1的过表达导致内源性视黄酸受体RARα和RXRα的表达上调，而RARβ的表达没有变化。转染细胞表现出对VIP的高亲和力结合（K(D)=0.2 nM）以及VIP介导的腺苷酸环化酶刺激，并且细胞周期动力学发生改变，在G1期的DNA指数接近三倍体。与野生型细胞相比，用VIP处理的SKNSH/VPAC1细胞表现出更分化的表型，其特征是组织转谷氨酰胺酶II增加，bcl-2免疫染色减少。视黄酸增强了VIP诱导的分化作用。这种分化导致异种移植模型中的增殖潜力降低。野生型SKNSH细胞在注射后13天内可使100%的裸鼠发生肿瘤生长，而转染VPAC1的SKNSH细胞在长达6个月的异种移植中未形成肿瘤。综上所述，这些数据支持以下推测：VIP对神经嵴分化的调节是通过VPAC1介导的，并且VPAC1的高表达可诱导神经母细胞瘤细胞分化并降低其致瘤性。
