Burnham D K, Gahring L C, Daynes R A
J Natl Cancer Inst. 1986 Jan;76(1):151-8.
Skin tumors were induced in (C3H/HeN X C3H/HeN-PGK-1a)F1 female mice, heterozygous at the X-linked phosphoglycerate kinase-1 (PGK-1) locus, by exposure to the carcinogenic influence of ultraviolet radiation (UVR), 3-methylcholanthrene [(MCA) CAS: 56-49-5], or benz[a]pyrene [(BP) CAS: 50-32-8]. An assessment of the clonal origin of these tumors was accomplished through an analysis of the PGK-1 enzyme phenotype expressed by the transformed cells. In vitro culture was employed as a means of depleting nontransformed cells of host origin from the induced tumors. Cultured lines derived from tumors induced by each of the above agents were found to express only one of the two enzyme forms encoded by the host genotype, consistent with the probability that all the UVR-, MCA-, and BP-induced tumors examined in this study were monoclonal in origin. For further substantiation of the monoclonality of UVR-induced tumors, 2 UVR-induced tumors were enzymatically dissociated immediately following excision from the primary hosts, and the resulting cell suspensions were cloned in soft agar. Upon analysis, each set of clones selected in soft agar expressed only a single PGK-1 enzyme form. To rule out the possibility that the apparent monoclonality of culture-adapted tumor lines was due to in vitro selection, tumors that arose in UVR-treated PGK-1a/b female heterozygote mice were transplanted into PGK-1a and PGK-1b homozygous recipients. These transplanted tumors expressed a single PGK-1 allozyme following growth in recipients that were genetically homozygous for the major PGK-1 enzyme form expressed by the tumor prior to transplantation. These data strongly support the concept that most, if not all, UVR-induced tumors are derived from the progeny of a single transformed cell. This observation is important to the understanding of the nature of tumor-specific transplantation antigens expressed by individual UVR-induced tumors and indicates that such antigens also are clone specific. In addition, the results of this study indicate that polyclonality does not play a significant role in the generation of cellular and phenotypic heterogeneity known to be present within individual UVR-induced tumors.
通过暴露于紫外线辐射（UVR）、3-甲基胆蒽[（MCA）CAS：56-49-5]或苯并[a]芘[（BP）CAS：50-32-8]的致癌影响，在X连锁磷酸甘油酸激酶-1（PGK-1）位点杂合的（C3H/HeN×C3H/HeN-PGK-1a）F1雌性小鼠中诱发皮肤肿瘤。通过分析转化细胞表达的PGK-1酶表型，对这些肿瘤的克隆起源进行了评估。采用体外培养作为从诱导肿瘤中去除宿主来源的未转化细胞的一种方法。发现源自上述每种试剂诱导的肿瘤的培养细胞系仅表达宿主基因型编码的两种酶形式之一，这与本研究中检测的所有UVR、MCA和BP诱导的肿瘤均起源于单克隆的可能性一致。为了进一步证实UVR诱导肿瘤的单克隆性，在从原发宿主切除后立即对2个UVR诱导的肿瘤进行酶解，将所得细胞悬液接种于软琼脂中进行克隆。经分析，在软琼脂中选择的每组克隆仅表达一种PGK-1酶形式。为了排除适应培养的肿瘤细胞系表面上的单克隆性是由于体外选择所致的可能性，将在UVR处理的PGK-1a/b雌性杂合子小鼠中出现的肿瘤移植到PGK-1a和PGK-1b纯合受体中。这些移植肿瘤在受体中生长后表达单一的PGK-1同工酶，受体对于移植前肿瘤表达的主要PGK-1酶形式是基因纯合的。这些数据有力地支持了这样一个概念，即大多数（如果不是全部）UVR诱导的肿瘤源自单个转化细胞的后代。这一观察结果对于理解单个UVR诱导肿瘤表达的肿瘤特异性移植抗原的性质很重要，并表明此类抗原也是克隆特异性的。此外，本研究结果表明多克隆性在个体UVR诱导肿瘤中已知存在的细胞和表型异质性的产生中不起重要作用。
