Suminami Y, Kashii Y, Law J C, Lin W C, Stanson J, Reichert T E, Rabinowich H, Whiteside T L
The University of Pittsburgh Cancer Institute and Department of Pathology, University of Pittsburgh School of Medicine, Pennsylvania 15213, USA.
Oncogene. 1998 Mar 12;16(10):1309-17. doi: 10.1038/sj.onc.1201640.
Interleukin-2 (IL-2) is recognized as a T cell growth factor. We have previously reported that human carcinoma cell lines are inhibited in growth by exogenous IL-2, which binds to the IL-2 receptor beta (IL-2Rbeta) chain ubiquitously expressed on the surface of tumor cells. A possibility was considered that IL-2Rbeta on carcinomas responsible for negative signaling was different from that expressed on hematopoietic cells. To investigate this possibility, mRNA for the IL-2Rbeta chain was amplified and compared in carcinoma and lymphoid cells. Using RT-PCR with pairs of sense-antisense oligonucleotide primers specific for the various regions of extracellular, transmembrane and intracellular domains of the IL-2Rbeta chain, we amplified mRNA obtained from three human carcinoma cell lines and human lymphoid cells as controls. The identity of the amplicons was confirmed by Southern analysis with the 32P-labeled cDNA probe coding for the entire span of the IL-2Rbeta chain. In addition, genomic DNA obtained from the tumor cell lines was sequenced to examine the possibility that a mutation is present in the gene coding for the intracellular IL-2Rbeta chain domain. No mutations or deletions were detected. The message for all three domains of the beta chain was identical in tumor cells and in normal lymphoid cells used as controls. Also, by Western blot and northern analyses no differences between IL-2Rbeta chain in tumors vs that expressed in lymphoid cells were demonstrable. The IL-2Rgamma chain, which participates in IL-2/IL-2R signaling pathway, was expressed in tumor cells. Expression of JAK1 transcripts in these cells was comparable to that in lymphocytes. However, RT-PCR analysis identified differences in expression of JAK3 splice variants (B and M) in tumor cells. These differences may be responsible for altered downstream signaling by IL-2. Overall, our data indicate that the same IL-2/IL-2R pathway is operative in human carcinomas and in normal epithelial or lymphoid cells.
白细胞介素-2（IL-2）被公认为一种T细胞生长因子。我们之前报道过，外源性IL-2可抑制人癌细胞系的生长，外源性IL-2与肿瘤细胞表面普遍表达的IL-2受体β（IL-2Rβ）链结合。有一种可能性被考虑到，即癌组织中负责负向信号传导的IL-2Rβ与造血细胞上表达的IL-2Rβ不同。为了研究这种可能性，对癌组织和淋巴细胞中IL-2Rβ链的mRNA进行了扩增和比较。使用针对IL-2Rβ链细胞外、跨膜和细胞内结构域各个区域的一对正义-反义寡核苷酸引物进行逆转录聚合酶链反应（RT-PCR），我们扩增了从三个人癌细胞系和作为对照的人淋巴细胞中获得的mRNA。用编码IL-2Rβ链全长的32P标记的cDNA探针进行Southern分析，证实了扩增产物的一致性。此外，对从肿瘤细胞系获得的基因组DNA进行测序，以检查编码细胞内IL-2Rβ链结构域的基因中是否存在突变。未检测到突变或缺失。在肿瘤细胞和用作对照的正常淋巴细胞中，β链所有三个结构域的信息是相同的。同样，通过蛋白质免疫印迹法（Western blot）和Northern分析，未发现肿瘤中的IL-2Rβ链与淋巴细胞中表达的IL-2Rβ链之间存在差异。参与IL-2/IL-2R信号通路的IL-2Rγ链在肿瘤细胞中表达。这些细胞中JAK1转录本的表达与淋巴细胞中的相当。然而，RT-PCR分析确定了肿瘤细胞中JAK3剪接变体（B和M）表达的差异。这些差异可能导致IL-2下游信号传导改变。总体而言，我们的数据表明，相同的IL-2/IL-2R途径在人癌组织以及正常上皮细胞或淋巴细胞中起作用。
