Pleiotropic signal transduction mediated by human CD30: a member of the tumor necrosis factor receptor (TNFR) family

CD30-induced up-regulation of the inhibitor of apoptosis genes cIAP1 and cIAP2 in anaplastic large cell lymphoma cells

OBJECTIVE

Expression of the cytokine receptor CD30 is a typical feature of anaplastic large cell lymphomas (ALCL). CD30-induced effects have a great impact on cell activation and viability.

MATERIALS AND METHODS

Using Karpas 299 cells, we performed differential display reverse transcriptase polymerase chain reaction (DDRT-PCR) to identify novel genes involved in CD30 signaling in ALCL. Activation of CD30 was induced by treatment with immobilized anti-CD30 antibody. RNA and protein expression were confirmed in different cell lines by Northern and Western blot analysis. Fluorescence-activated cell sorting (FACS) analysis was applied to examine cell viability. Nuclear factor kappaB (NFkappaB) pathways were blocked using a specific inhibitor.

RESULTS

We found strongly enhanced expression of the cellular inhibitor of apoptosis cIAP1 and cIAP2 in Karpas 299 cells stimulated with anti-CD30. Furthermore, we showed that CD30-regulated expression of cIAP1 and cIAP2 was mediated by NFkappaB. Induction of NFkappaB, cIAP1, and cIAP2 correlated with partial protection from apoptotic cell death caused by etoposide. Correspondingly, inhibition of the NFkappaB pathway not only prevented the prevalent antiapoptotic effects mediated by CD30, but even led to CD30-induced apoptosis. Finally, we found enhanced expression of cIAP1 and cIAP2 in several other ALCL cell lines and the HD-derived cell line HDLM-2 upon CD30 stimulation.

CONCLUSIONS

Our results indicate that CD30-mediated protection from apoptosis is a common feature of CD30(+) cells. Therefore, CD30-induced signaling may have a significant impact on the clinical outcome of patients with ALCL.

Expression and a role of CD30 in regulation of T-cell activity

CD30 receptor has been known for almost 20 years, but its expression and activity are still the subject of many investigations. Its expression was found in different malignancies, and most of the studies regarding CD30 focus on its role in lymphomas. The progress that has already been made in this field is reflected in implementation of CD30 as a target for immunotoxin, which has been tested in phase I study in treating Hodgkin lymphoma. CD30 is present also on normal, activated T cells of all cytokine profiles. However, increased density of CD30 and CD30-mediated Th2 cytokine production provide evidence of its role in determining the activity of T cells toward synthesis of cytokines and involvement in reactions of Th2 characteristics. Pleiotropic signaling mediated by CD30 does not implicate this receptor just as a cytokine costimulator; it proves to be important in several different activities of T cells.

Caspase-mediated cell death in hematological malignancies: theoretical considerations, methods of assessment, and clinical implications

Apoptosis, the caspase-mediated cell death, plays an important role in the etiology, pathogenesis and therapy of a variety of diseases. Abnormalities of apoptosis regulation, resulting in either its inhibition or enhancement, play a key role in the development of various malignant hematological disorders. Several routine and new therapeutic strategies in Oncohematology are based on apoptosis modulation. Cytotoxic effects of most antineoplastic drugs are based on induction of apoptosis. The accurate estimate of incidence of apoptosis, therefore, is of importance in Oncohematology. In this review we provide an overview of the methods designed to measure the incidence of apoptosis, including the recently developed assays that are based on detection of caspases activation. We also review recent findings on the role of caspase-mediated cell death in hematological malignancies and discuss their clinical implications, including new therapeutical strategies that evolve from these findings.