Antitumor Activity of an Oncolytic Adenoviral-CD40 Ligand (CD154) Transgene Construct in Human Breast Cancer Cells

Abstract

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-1a 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 of1. Incorporation of the CD40L transgene reduced the effective dose needed to achieve 50% growth inhibition (ED 50 ) by f10-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-231xenograft 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.

Oncolytic Immunotherapy of Advanced Solid Tumors with a CD40L-Expressing Replicating Adenovirus: Assessment of Safety and Immunologic Responses in Patients

“…Therefore, it may be of relevance that it can be augmented by arming the virus with immune stimulatory molecules, such as CD40 ligand (CD40L). Preclinical studies have suggested that this approach can result in enhanced antitumor activity but human data has been lacking heretofore (11). Soluble CD40L (sCD40L) has been shown to mediate various antitumor activities in vitro and in vivo including direct growth inhibition and induction of apoptosis in different human tumor types (11)(12)(13).…”

“…Preclinical studies have suggested that this approach can result in enhanced antitumor activity but human data has been lacking heretofore (11). Soluble CD40L (sCD40L) has been shown to mediate various antitumor activities in vitro and in vivo including direct growth inhibition and induction of apoptosis in different human tumor types (11)(12)(13). CD40L immunotherapy has also been shown to target the chemoresistant subpopulation of cancer cells (14) and has been suggested to sensitize chemoresistant tumors to cytotoxic drugs (15,16).…”

Anti-tumor activity of gene transfer of the membrane-stable CD40L mutant into lung cancer cells

“…CD40L transgene expression in human breast (9), ovarian (21), cervical (22) colon (26), bladder (27), non-small cell lung (28), skin (29), and squamous epithelial carcinoma cells (30) was found to produce a direct growth-inhibitory effect through apoptotic induction and/or cell cycle blockage with no overt side effects on their normal counterparts. The pro-apoptotic effects of CD40L are revealed upon disruption of the PI3 kinase/mTOR and ERK signaling pathways or inhibitor of de novo protein synthesis (13).…”

“…5-FU) or novel modalities (e.g. oncolytic viruses) also have displayed enhanced efficacy in pre-clinical animal models (9).…”

The impact of hypoxia on oncolytic virotherapy

“…88 In another study, the gene encoding CD40 ligand was used due to its immunostimulatory activity. 89 Post et al made an oncolytic Ad armed with an interleukin-4 gene (HYPR-Ad-IL4). The interleukin-4 cytokine was chosen for its ability to induce a strong host antitumor immune response and for its potential antiangiogenic activity.…”