Heterogeneity in XXXX receptor expression and subunit structure in squamous cell carcinoma of @entity135 : differential sensitivity to chimeric fusion proteins comprised of @entity4047 and a mutated form of Pseudomonas exotoxin.

@entity1 @entity135 @entity137 @entity9597 @entity4047 @entity5 @entity9596 @entity213
@entity213 ( @entity213 ) is characterized by a high proliferation index and marked propensity for local invasion resulting in poor prognosis for these @entity1 . To develop @entity5 -targeted novel therapeutic agents, here we demonstrate that @entity213 cell lines express receptors for an immune regulatory cytokine, @entity4047 . By reverse transcription-PCR (RT-PCR), we found that 16 @entity213 cell lines express equally strong RT-PCR positive bands for mRNA of IL-13Ralpha1 and @entity9597 chains. However, only three cell lines, HN12, YCUM911, and KCCT873, expressed a strong band for transcripts for @entity9596 chain and five cell lines, YCUL891, KCCTC871, KCCL871, KCCTCM901, and RPMI 2650 expressed faint bands. Transcripts for IL-2Rgamma(c) chain were absent in all of the cell lines tested. Indirect immunofluorescence analysis for four different receptor chains confirmed RT-PCR results and showed pronounced expression of @entity9596 protein in three high @entity9596 expressing cell lines. All of the cell lines were equally positive for IL-13Ralpha1 and @entity9597 chains. Receptor-binding studies demonstrated that @entity9596 -positive cell lines expressed a high density of @entity4047 receptors. Using two chimeric proteins composed of @entity4047 and mutated forms of Pseudomonas exotoxin ( @entity4047 -PE38 or @entity4047 -PE38QQR), we found that these two fusion toxins were highly and equally cytotoxic to @entity9596 -positive @entity213 , whereas @entity9596 -negative cell lines showed low or no sensitivity to @entity4047 toxins. To additionally substantiate the critical role of the @entity9596 chain in @entity9596 -mediated @entity137 , two @entity135 cell lines (YCUMS861 and KB), devoid of the transcripts of this chain, were transfected with @entity9596 cDNA and then tested for @entity137 . Transient transfection of the @entity9596 chain highly sensitized these cells to @entity4047 toxin as compared with mock-transfected control cells. Thus, our results indicate that @entity9596 is present in 50% @entity213 cell lines; of these, 19% are high expresser for this chain and respond to @entity4047 cytotoxin. Thus, @entity4047 cytotoxin may be a useful agent for high @entity9596 -expressing @entity213 .
