Antitumor activity of an oncolytic adenoviral-CD40 ligand (CD154) transgene construct in human breast cancer cells.

PURPOSE: CD40 ligand (CD40L, CD154) plays a central role in immunoregulation and also directly modulates epithelial cell growth and differentiation. We previously showed that the CD40 receptor is commonly expressed in primary breast cancer tissues. In this proof-of-principle study, we examined the breast cancer growth-regulatory activities of an oncolytic adenoviral construct carrying the CD40L transgene (AdEHCD40L). EXPERIMENTAL DESIGN: In vitro and in vivo evaluations were carried out on AdEHCD40L to validate selective viral replication and CD40L transgene activity in hypoxia inducing factor-1alpha and estrogen receptor-expressing human breast cancer cells. RESULTS: AdEHCD40L inhibited the in vitro growth of CD40+ human breast cancer lines (T-47D, MDA-MB-231, and BT-20) by up to 80% at a low multiplicity of infection of 1. Incorporation of the CD40L transgene reduced the effective dose needed to achieve 50% growth inhibition (ED50) by approximately 10-fold. In contrast, viral and transgene expression of AdEHCD40L, as well its cytotoxicity, was markedly attenuated in nonmalignant cells. Intratumoral injections with AdEHCD40L reduced preexisting MDA-MB-231 xenograft growth in severe combined immunodeficient mice by >99% and was significantly more effective (P<0.003) than parental virus AdEH (69%) or the recombinant CD40L protein (49%). This enhanced antitumor activity correlated with cell cycle blockade and increased apoptosis in AdEHCD40L-infected tumor cells. CONCLUSIONS: These novel findings, together with the previously known immune-activating features of CD40L, support the potential applicability of AdEHCD40L for experimental treatment of human breast cancer.

Immunoglobulin M myeloma: evaluation of molecular features and cytokine expression.

Immunoglobulin (Ig) M myeloma is a distinct entity with features of multiple myeloma (MM) and Waldenstrom's macroglobulinemia (WM). The malignant cells in IgM myeloma have a distinctive chromosomal translocation that differentiates them from WM. These cells are postgerminal-center in origin with isotype-switch transcripts. They appear to be arrested at a point of maturation between that of WM and MM. Preliminary data indicate that a pattern of osteoclast-activating factor and osteoprotegerin expression similar to that observed in classic MM is present in IgM myeloma. Additional studies on patients with this rare tumor may provide further insight into the pathogenesis of bone disease in plasma cell dyscrasias.

Human monoclonal macroglobulins with antibody activity.

Assays for specific antigen-binding activity were performed on sera from 172 patients with monoclonal macroglobulinemia defined by immunofixation electrophoresis. The sera were collected between 1970 and 2002. Mean IgM level was 1,409 mg/dL with a range from 70 to 6,800. Cryoglobulins were identified in 15.3% (26/170 sera: 12 trace, five single component, and nine mixed IgM-IgG). Rheumatoid factor (RF) was detected in 19 of 151 (12.6%) samples with titers ranging from 1:80 to 1:327,680. Among the nine mixed IgM-IgG cryos, eight were RF-positive and six of six displayed positivity for hepatitis C virus. Cold agglutinins (CA) were present in 8.5% (10/117) of sera with anti-I titers between 1:512 and 1:65,536. IgM binding to a series of glycosaminoglycan oligosaccharides, glycolipids, and glycoprotein antigens was found in 75 samples (43%). IgM binding to antigens having known associations to polyneuropathies occurred in 20 patients (12%). Antinuclear antibody (ANA) was documented in 10.7% (18/169) of sera. Anti-DNA activity was absent in all samples tested. Sera from 71% of patients with monoclonal macroglobulinemia in this series exhibited binding to autoantigens. Some of these immune complexes resulted in clinically significant manifestations. Our results suggest that many monoclonal immunoglobulins may be functional antibodies rather than "paraproteins." Characterization of antigen-binding activities may provide insight into the pathogenesis of monoclonal gammopathies.