Distinct effects of CD30 and Fas signaling in cutaneous anaplastic lymphomas: A possible mechanism for disease progression

Lymphomatoid papulosis is part of a spectrum of CD30+ cutaneous lymphoproliferative disorders characterized by spontaneous tumor regression, The mechanism(s) of regression is unknown, In a recent study, a selective increase in CD30 ligand expression in regressing lesions of lymphomatoid papulosis and cutaneous CD30+ anaplastic large cell lymphoma was shown, suggesting that activation of the CD30 signaling pathway may be responsible for tumor regression, whereas no difference in Fas/Fas ligand expression was found between regressing and nonregressing lesions. Therefore we tested the effects of CD30 and Fas activation on three CD30+ cutaneous lymphoma cell lines (Mac-1, Mac-2A, JK) derived from nonregressing tumors of two patients who had progressed from lymphomatoid papulosis to systemic anaplastic large cell lymphoma, To evaluate the effects of CD30 signaling, the cell lines were incubated with a CD30 agonistic antibody, HeFi-1. Proliferative responses, mitogen-activated protein kinase, and nuclear factor KB activities were determined with and without CD30 activation. Mac-1 and Mac-2A showed increased proliferative responses to incubation with CD30 activating antibody, HeFi-1, Inhibition of the mitogen-activated protein kinase activity caused growth inhibition of the Mac-1, Mac-2A, and JK cell lines, Activation of the Fas pathway induced apoptosis in all three cell lines, Taken together, these findings suggest that resistance to CD30-mediated growth inhibition provides a possible mechanism for escape of cutaneous anaplastic large cell lymphoma from tumor regression, Mitogen-activated protein kinase inhibitors are potential therapeutic agents for the treatment of advanced cutaneous anaplastic large cell lymphoma.