Fischer-Huchzermeyer Susan, Dombrowski Anna, Hagel Christian, Mautner Victor F, Schittenhelm Jens, Harder Anja
Institute of Neuropathology, University Hospital Münster, Münster, Germany.
Clinics of Radiotherapy, HELIOS Clinic Berlin-Buch, Berlin, Germany.
Am J Pathol. 2017 Jul;187(7):1623-1632. doi: 10.1016/j.ajpath.2017.02.021. Epub 2017 May 11.
Malignant peripheral nerve sheath tumors (MPNSTs) are aggressive neoplasms that commonly occur in patients with neurofibromatosis type 1 (NF1). Effective chemotherapy is not available. To characterize a therapeutic target for treatment, we investigated the role of cellular retinoic acid binding protein 2 (CRABP2) in MPNST in vitro. CRABP2 is a transcriptional co-activator of retinoic acid signaling. Although overexpression of CRABP2 is described in several cancers, it has not yet been studied in MPNSTs. We investigated CRABP2 expression in cultured Schwann cells and formalin-fixed, paraffin-embedded specimens of human peripheral nerve sheath tumors. A transient knockdown of CRABP2 was established in human NF1-associated MPNST cell lines (S462, T265, NSF1), and functional effects on viability, proliferation, apoptosis, and cytotoxicity were monitored. Finally, a 45-pathway reporter assay was performed in knockdown cells. Expression of CRABP2 was found in epithelium, fibroblasts, and tumor Schwann cells of skin, neurofibromas, and MPNSTs. In contrast, normal skin Schwann cells (NF1, NF1) did not express CRABP2. In the absence of retinoic acid, MPNST cells depleted of CRABP2 had reduced viability and proliferation, induction of apoptosis and cytotoxicity, and up-regulation of the type 1 interferon pathway. These data suggest a retinoic acid-independent, non-tumor suppressor role of CRABP2 for the survival of MPNST cells in vitro. Targeting CRABP2 overexpression may represent a unique approach for the treatment of human MPNSTs.
恶性外周神经鞘瘤(MPNSTs)是一种侵袭性肿瘤,常见于1型神经纤维瘤病(NF1)患者。目前尚无有效的化疗方法。为了确定治疗靶点,我们在体外研究了细胞视黄酸结合蛋白2(CRABP2)在MPNST中的作用。CRABP2是视黄酸信号的转录共激活因子。虽然在几种癌症中都有CRABP2过表达的描述,但尚未在MPNST中进行研究。我们研究了CRABP2在培养的施万细胞以及人外周神经鞘瘤的福尔马林固定石蜡包埋标本中的表达。在人NF1相关的MPNST细胞系(S462、T265、NSF1)中建立了CRABP2的瞬时敲低,并监测其对细胞活力、增殖、凋亡和细胞毒性的功能影响。最后,在敲低细胞中进行了45通路报告基因检测。在皮肤、神经纤维瘤和MPNST的上皮细胞、成纤维细胞和肿瘤施万细胞中发现了CRABP2的表达。相比之下,正常皮肤施万细胞(NF1、NF1)不表达CRABP2。在没有视黄酸的情况下,CRABP2缺失的MPNST细胞活力和增殖降低,凋亡和细胞毒性诱导增加,1型干扰素通路上调。这些数据表明,CRABP2在体外对MPNST细胞存活具有视黄酸非依赖性的非肿瘤抑制作用。靶向CRABP2过表达可能是治疗人类MPNST的一种独特方法。