Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
Transl Oncol. 2010 Aug 1;3(4):204-17. doi: 10.1593/tlo.09316.
Malignant melanoma has increased incidence worldwide and causes most skin cancer-related deaths. A few cell surface antigens that can be targets of antitumor immunotherapy have been characterized in melanoma. This is an expanding field because of the ineffectiveness of conventional cancer therapy for the metastatic form of melanoma. In the present work, antimelanoma monoclonal antibodies (mAbs) were raised against B16F10 cells (subclone Nex4, grown in murine serum), with novel specificities and antitumor effects in vitro and in vivo. MAb A4 (IgG2ak) recognizes a surface antigen on B16F10-Nex2 cells identified as protocadherin beta(13). It is cytotoxic in vitro and in vivo to B16F10-Nex2 cells as well as in vitro to human melanoma cell lines. MAb A4M (IgM) strongly reacted with nuclei of permeabilized murine tumor cells, recognizing histone 1. Although it is not cytotoxic in vitro, similarly with mAb A4, mAb A4M significantly reduced the number of lung nodules in mice challenged intravenously with B16F10-Nex2 cells. The V(H) CDR3 peptide from mAb A4 and V(L) CDR1 and CDR2 from mAb A4M showed significant cytotoxic activities in vitro, leading tumor cells to apoptosis. A cyclic peptide representing A4 CDR H3 competed with mAb A4 for binding to melanoma cells. MAb A4M CDRs L1 and L2 in addition to the antitumor effect also inhibited angiogenesis of human umbilical vein endothelial cells in vitro. As shown in the present work, mAbs A4 and A4M and selected CDR peptides are strong candidates to be developed as drugs for antitumor therapy for invasive melanoma.
恶性黑素瘤的发病率在全球范围内呈上升趋势，是导致大多数皮肤癌相关死亡的主要原因。已经鉴定出一些可作为抗肿瘤免疫治疗靶点的黑素瘤细胞表面抗原。由于常规癌症疗法对转移性黑素瘤无效，该领域正在不断扩展。在本研究中，针对在鼠血清中生长的 B16F10 细胞（亚克隆 Nex4）产生了抗黑素瘤单克隆抗体（mAb），这些 mAb 具有新的特异性，在体外和体内具有抗肿瘤作用。MAb A4（IgG2ak）识别 B16F10-Nex2 细胞表面的一种抗原，鉴定为原钙黏蛋白β13。它对 B16F10-Nex2 细胞具有细胞毒性，在体外也能杀伤人类黑素瘤细胞系。MAb A4M（IgM）与通透的鼠肿瘤细胞核强烈反应，识别组蛋白 1。虽然它在体外没有细胞毒性，但与 mAb A4 相似，mAb A4M 可显著减少经静脉注射 B16F10-Nex2 细胞的小鼠肺结节数。来自 mAb A4 的 V(H)CDR3 肽和来自 mAb A4M 的 V(L)CDR1 和 CDR2 在体外具有显著的细胞毒性活性，导致肿瘤细胞凋亡。代表 A4 CDR H3 的环肽与 mAb A4 竞争与黑素瘤细胞结合。MAb A4M 的 CDR L1 和 L2 除了具有抗肿瘤作用外，还能抑制人脐静脉内皮细胞的血管生成。如本研究所示，mAb A4 和 A4M 以及选定的 CDR 肽是作为侵袭性黑素瘤抗肿瘤治疗药物开发的有力候选物。
