Signal transduction abnormalities in T lymphocytes from patients with advanced renal carcinoma: Clinical relevance and effects of cytokine therapy

Studies have demonstrated abnormalities of the CD3/T-cell antigen receptor (TCR) and pathways of signal transduction in T lymphocytes from animals and patients with advanced malignancy. Diminished expression of TCRζ and p56(1ck) that are associated with the TCR and reduced nuclear localization of RelA containing nuclear factor κB (NFκB) complexes have been noted. These defects have been described in T cells from patients with malignant melanoma, renal cell carcinoma (RCC), ovarian cancer, and colorectal cancer. Preliminary observations also indicate possible correlation with clinical variables such as stage in selected instances. To further characterize altered expression of TCRζ, p56(1ck), and impaired activation of NFκB, T lymphocytes were obtained from 65 patients with RCC, the majority of whom were receiving combination cytokine therapy [interleukin (IL)-2, IFNα-containing regimens] and 37 control individuals. In 29 of these patients, levels of TCRζ and p56(1ck) were determined by Western blots of T- cell lysates and semiquantitated using densitometry. Relative levels were then correlated with a series of clinical variables including response to therapy, performance status, survival, disease sites, age, and others. In another group of 28 patients (three individuals from the first group), the frequency of abnormal NFκB activation was studied using electrophoretic mobility shift assays after activation of T cells with phorbol myristate acetate/ionomycin or anti-CD3 monoclonal antibody. Changes in these signaling molecules during cytokine treatment were also investigated. TCRζ and p56(1ck) were detected in the peripheral blood T cells in 27 of 29 patients, and overall, reduced levels were noted visually in 12 of 29 (41%) and 13 of 29 (45%) individuals, respectively. When levels were semiquantitated using densitometry, significant decreases of TCRζ (P = 0.029) and p56(1ck) (P = 0.029) but not CD3ε (P = 0.131), compared with control levels, were found. In patients treated with IL-2/IFNα-based therapy, relative levels of TCRζ increased significantly (P = 0.002) on day 15 of cycle one compared with the baseline. Correlations of TCRζ or p56(1ck) levels with response or disease variables, except for lower TCRζ levels (P < 0.001) in the presence of bone metastases, were not found. Abnormal NFκB activation after stimulation with phorbol myristate acetate/ionomycin and/or anti-CD3 monoclonal antibody was found in 59% of patients (17 of 28) and was not accounted for by the advanced age of the study cohort. Activation of NFκB in peripheral blood T cells was inducible during cytokine therapy in four of six individuals who displayed impaired NFκB activity prior to therapy. Moreover, impaired activation of NFκB does not appear linked to a reduction of TCRζ expression, because in five patients, normal TCRζ levels were present although κB binding was not inducible. In the majority of patients with advanced RCC, peripheral blood T cells express TCRζ and p56(1ck), and in a subset, reduced levels of these TCRζ associated molecules are seen that may increase during cytokine-based therapy. Abnormal activation of NFκB is also present in >50% of patients and may also revert to normal during IL-2/IFNα-based treatment. This alteration in NFκB activation occurred in the presence of normal expression of TCRζ- associated signaling elements. The clinical significance of these findings remains unclear.