Cytosine Deaminase-Uracil Phosphoribosyltransferase and Interleukin (IL)-12 and IL-18: A Multimodal Anticancer Interface Marked by Specific Modulation in Serum Cytokines

Abstract

Purpose: To test the effects of a new combination, cytosine deaminase (CD) + uracil phosphoribosyltransferase (UPRT)^mediated gene-directed enzyme prodrug therapy (GDEPT) with interleukin (IL)-12 and IL-18, on (a) growth of murine prostate and remote tumor deposits, (b) mouse survival, and (c) T helper (Th) 1/Th2 serum cytokine balance with a special focus to assess correlation with tumor burden/survival. Experimental Design: Efficacy of intraprostatic administration of adenovirally delivered murine IL-12 and IL-18 against orthotopic RM1 tumors and lung pseudometastases was assessed in C57BL/6 mice. At necropsy, tumor growth, lung colony counts, effects on immune cell infiltration, vasculature, apoptosis, and proliferation were estimated. Next, CDUPRT-GDEPT + cytokines were tested at suboptimal doses in mice with RM1CDUPRT prostate tumors/RM1 lung deposits and analyzed as above. Effects on mouse survival were also assessed. Host immune responses to different treatments were assessed by monitoring 11serum cytokines using Luminex technology. Results: Our data show that IL-12 and IL-18, when combined with CDUPRT-GDEPT, caused significant reduction in local RM1 tumors and lung colonies with enhanced long-term survival versus individual treatments. A dramatic enhancement of tumor infiltration by a wider repertoire of immune cells and disruption of vasculature implied the combination to be more immunostimulatory and antiangiogenic. Remarkably, lowering of serum IL-4 and monocyte chemoattractant protein-1 (MCP-1) was consistently associated with lower tumor burden (local and systemic), and this, rather than an increase inTh1cytokines, better predicted treatment efficacy. In addition, mouse survival correlated with substantially higher cytokine (Th1/Th2) levels after treatment. Conclusion: Locoregional application of CDUPRT-GDEPTand IL-12/IL-18 was effective against local and systemic prostate cancer and improved survival. Monitoring serum levels of IL-4 and MCP-1may accurately reflect tumor burden and, hence, host response to therapy.Heterogeneity of clinical prostate cancer has culminated in inadequacy of single-treatment regimens and inefficient patient management. An urgent need has emerged for (a) new combination regimens that can be given into the primary tumor with systemic effects and without toxicities and (b) design of preclinical screening to generate clinically relevant data.Immunostimulatory strategies have the potential to combat cancer and generate long-term anticancer effects. However, poorly immunogenic tumors and immunocompromised patients pose a challenge. The in situ amplification of cytotoxicity via local and distant bystander effects by locally delivered gene-directed enzyme prodrug therapies (GDEPT) is shown to be inflammatory [T cells, macrophages, and natural killer (NK) cells], and several studies support the concept that further enhancement is possible using cytokines (1). This was first shown when IL-2 combined with thymidine kinasebased GDEPT (HSV-tk) was found to be more potent aga...

Immunotherapeutic Approach for Better Management of Cancer - Role of IL-18

“…Effects of a new combination, cytosine deaminase (CD) + uracil phosphoribosyl transferase (UPRT)-mediated gene-directed enzyme prodrug therapy (GDEPT) with interleukin (IL)-12 and IL-18, was effective against local and systemic prostate cancer and improved survival. Monitoring serum levels of IL-4 and MCP-1 may accurately reflect tumor burden and, hence, host response to therapy (Khatri et al, 2009).…”

Molecular Chemotherapy and Chemotherapy: A New Front against Late-Stage Hormone-Refractory Prostate Cancer

“…At necropsy (day 16), tumors/organs and sera were collected and stored as described above. The lungs were fixed in Bouin's reagent to facilitate lung colony counting as described (18).…”

“…Sera from mice (25 mL in mouse serum matrix) were analyzed (n ¼ 4-5) using a Multiplex Mouse Cytokine/ Chemokine Magna Bead Panel (Millipore) for murine Th2 cytokines/chemokines, IL-4, IL-6, IL10, and MCP-1 as described previously (22). Briefly, 2-fold serial dilutions of standards (10,000-3.2 pg/mL) were done, and the samples were incubated with a cocktail of antibody-immobilized beads overnight at 4 C; this was followed by incubation with biotinylated detection antibody cocktail and then incubation with streptavidin-phycoerythrin.…”

“…Tumors were frozen and acetone-fixed, and 5-mm sections were stained to evaluate apoptosis by in situ detection using the M-30Cytodeath Kit (Alexis Biochemicals), for infiltrating T lymphocytes (CD4 þ and CD8a þ ) and macrophages (F4/80 þ ), and positively stained cells were scored by light microscopy as described (18,20). The antibody details are listed in Supplementary Table S1.…”

“…We have previously shown, in evaluating a combination of cytosine deaminase-uracil phosphoribosyl transferase with interleukin (IL)-12 and IL-18 gene therapy against RM1 tumors, that lowering of serum IL-4 and monocyte chemotactic protein (MCP)-1 was consistently associated with lower tumor burden (local and systemic; ref. 18). Overall, the study indicated that a change in the Th2 cytokine/chemokines was a more reliable predictor of tumor burden or response to therapy.…”